NOTE 16. Business Segments  3Ms businesses are organized, managed and internally grouped into segments based on differences in markets, products, technologies and services. 3M manages its operations in four business segments: Safety and Industrial; Transportation and Electronics; Health Care; and Consumer. 3Ms four business segments bring together common or related 3M technologies, enhancing the development of innovative products and services and providing for efficient sharing of business resources. Transactions among reportable segments are recorded at cost. 3M is an integrated enterprise characterized by substantial intersegment cooperation, cost allocations and inventory transfers. Therefore, management does not represent that these segments, if operated independently, would report the operating income information shown. The difference between operating income and pre-tax income relates to other expense (income), which is not allocated to business segments. Further information about which is included in Note 6.  Effective in the first quarter of 2020, in a continuing effort to improve the alignment of its businesses around customers and markets, the Company made the following changes:  Continued alignment of customer account activity  As part of 3Ms regular customer-focus initiatives, the Company realigned certain customer account activity (sales district) to correlate with the primary divisional product offerings in various countries and reduce complexity for customers when interacting with multiple 3M businesses. This largely impacted the amount of dual credit certain business segments receive as a result of sales district attribution. 3M business segment reporting measures include dual credit to business segments for certain sales and operating income. This dual credit is based on which business segment provides customer account activity with respect to a particular product sold in a specific country. As a result, previously reported aggregate business segment net sales and operating income for the total year 2019 decreased $42 million and $10 million, respectively, offset by corresponding decreases in the Elimination of Dual Credit net sales and operating income amounts.  Additional actions impacting product line alignments  The remaining retail auto care product lines formerly in the Automotive Aftermarket Division (within the Safety and Industrial business segment), were realigned to the Construction and Home Improvement Division (within the Consumer business segment). This change resulted in a decrease of previously reported net sales and operating income for total year 2019 of $35 million and $11 million, respectively, in the Safety and Industrial business segment, offset by a corresponding increase in net sales and operating income within the Consumer business segment.  In addition, certain product lines were realigned within business segments. The transdermal drug delivery components business, formerly included in the Drug Delivery Systems Division, was realigned to the Medical Solutions Division (both of which are within the Health Care business segment) and the paint protection film business, formerly included in the Automotive and Aerospace Division, was realigned to the Commercial Solutions Division (both of which are within the Transportation and Electronics business segment).  The financial information presented herein reflects the impact of the preceding changes for all periods presented.  Business Segment Information            Three months ended   March 31, (Millions) 2020 2019 Net Sales        Safety and Industrial $ 2,935 $ 2,963  Transportation and Electronics  2,238  2,355  Health Care  2,103  1,738  Consumer  1,256  1,200  Corporate and Unallocated  1  22  Elimination of Dual Credit  (458)  (415)  Total Company $ 8,075 $ 7,863          Operating Income        Safety and Industrial $ 726 $ 637  Transportation and Electronics  484  522  Health Care  456  464  Consumer  269  235  Corporate and Unallocated  (156)  (625)  Elimination of Dual Credit  (116)  (97)  Total Company $ 1,663 $ 1,136   Corporate and unallocated operating income includes a variety of miscellaneous items, such as corporate investment gains and losses, certain derivative gains and losses, certain insurance-related gains and losses, certain litigation and environmental expenses, corporate restructuring charges and certain under- or over-absorbed costs (e.g. pension, stock-based compensation) that the Company may choose not to allocate directly to its business segments. Corporate and Unallocated also includes sales, costs, and income from contract manufacturing, transition services and other arrangements with the acquirer of the Communication Markets Division following its 2018 divestiture through 2019. Because this category includes a variety of miscellaneous items, it is subject to fluctuation on a quarterly and annual basis.  3M business segment reporting measures include dual credit to business segments for certain sales and related operating income. Management evaluates each of its four business segments based on net sales and operating income performance, including dual credit reporting to further incentivize sales growth. As a result, 3M reflects additional (dual) credit to another business segment when the customer account activity (sales district) with respect to the particular product sold to the external customer is provided by a different business segment. This additional dual credit is largely reflected at the division level. For example, privacy screen protection products are primarily sold by the Display Materials and Systems Division within the Transportation and Electronics business segment; however, certain sales districts within the Consumer business segment provide the customer account activity for sales of the product to particular customers. In this example, the non-primary selling segment (Consumer) would also receive credit for the associated net sales initiated through its sales district and the related approximate operating income. The assigned operating income related to dual credit activity may differ from operating income that would result from actual costs associated with such sales. The offset to the dual credit business segment reporting is reflected as a reconciling item entitled Elimination of Dual Credit, such that sales and operating income in total are unchanged.