investment-grade securities.

The company’s future debt level is dependent primarily on results of operations, the capital program and cash that may be generated from asset dispositions. Based on its high-quality debt ratings, the company believes that it has substantial borrowing capacity to meet unanticipated cash requirements. During extended periods of low prices for crude oil and natural gas and narrow margins for refined products and commodity chemicals, the company can also modify capital spending plans to provide flexibility to continue paying the common stock dividend and also remain committed to retaining the company’s high-quality debt ratings.

Committed Credit Facilities Information related to committed credit facilities is included in Note 20, Short-Term Debt, on page FS-52.

Common Stock Repurchase Program In July 2010, the Board of Directors approved an ongoing share repurchase program with no set term or monetary limits. The company did not acquire any shares under the program in 2016 or 2015. From the inception of the program through 2014, the company had purchased 180.9 million shares for $20.0 billion.

Capital and Exploratory Expenditures

Capital and exploratory expenditures by business segment for 2016, 2015 and 2014 are as follows:

Total expenditures for 2016 were $22.4 billion, including $3.8 billion for the company’s share of equity-affiliate expenditures, which did not require cash outlays by the company. In 2015 and 2014, expenditures were $34.0 billion and $40.3 billion, respectively, including the company’s share of affiliates’ expenditures of $3.4 billion and $3.5 billion, respectively.

Of the $22.4 billion of expenditures in 2016, 90 percent, or $20.1 billion, related to upstream activities. Approximately 92 percent was expended for upstream operations in both 2015 and 2014. International upstream accounted for 77 percent of the worldwide upstream investment in 2016 and 76 percent in 2015 and 2014.

The company estimates that 2017 capital and exploratory expenditures will be $19.8 billion, including $4.7 billion of spending by affiliates. This planned reduction, compared to 2016 expenditures, reflects current crude oil market conditions, major capital projects nearing completion and the targeting of shorter-cycle projects. Approximately 87 percent of the total, or $17.3 billion, is budgeted for exploration and production activities. Approximately $8.5 billion of planned upstream capital spending relates to base producing assets, including about $2.5 billion for shale and tight resource investments, the majority of which is slated for Permian Basin developments in Texas and New Mexico. Another $7 billion is related to major capital projects already underway, including approximately $2 billion for completion of the Gorgon and Wheatstone LNG projects in Australia and $3 billion of affiliate expenditures associated with the Future Growth and Wellhead Pressure Management Project at the Tengiz Field in Kazakhstan. Global exploration funding accounts for approximately $1 billion, and the remainder is primarily related to early stage projects supporting potential future development opportunities. The company will