Financial data for reportable segments are as follows: Three Months Ended June 30, 2019 Gathering and Processing Transportation (1) and Storage Eliminations Total (In millions) Product sales $ 379 $ 114 $ (100 ) $ 393 Service revenues 208 138 (4 ) 342 Total Revenues 587 252 (104 ) 735 Cost of natural gas and natural gas liquids (excluding depreciation and amortization shown separately) 297 123 (103 ) 317 Operation and maintenance, General and administrative 75 50 (1 ) 124 Depreciation and amortization 78 32  110 Taxes other than income tax 10 7  17 Operating income $ 127 $ 40 $  $ 167 Total Assets $ 9,881 $ 5,775 $ (3,247 ) $ 12,409 Capital expenditures $ 90 $ 19 $  $ 109 Three Months Ended June 30, 2018 Gathering and Processing Transportation (1) and Storage Eliminations Total (In millions) Product sales $ 465 $ 149 $ (113 ) $ 501 Service revenues 176 128  304 Total Revenues 641 277 (113 ) 805 Cost of natural gas and natural gas liquids (excluding depreciation and amortization shown separately) 411 147 (114 ) 444 Operation and maintenance, General and administrative 76 47  123 Depreciation and amortization 63 33  96 Taxes other than income tax 10 6  16 Operating income $ 81 $ 44 $ 1 $ 126 Total assets as of December 31, 2018 $ 9,874 $ 5,805 $ (3,235 ) $ 12,444 Capital expenditures $ 143 $ 42 $  $ 185 _____________________ (1) See Note 8 for discussion regarding ownership interests in SESH and related equity earnings included in the transportation and storage segment for the three and six months ended June 30, 2019 and 2018 . Six Months Ended June 30, 2019 Gathering and Processing Transportation (1) and Storage Eliminations Total (In millions) Product sales $ 802 $ 281 $ (247 ) $ 836 Service revenues 415 287 (8 ) 694 Total Revenues 1,217 568 (255 ) 1,530 Cost of natural gas and natural gas liquids (excluding depreciation and amortization shown separately) 657 292 (254 ) 695 Operation and maintenance, General and administrative 159 95 (1 ) 253 Depreciation and amortization 152 63  215 Taxes other than income tax 21 14  35 Operating income $ 228 $ 104 $  $ 332 Total Assets $ 9,881 $ 5,775 $ (3,247 ) $ 12,409 Capital expenditures $ 197 $ 55 $  $ 252 Six Months Ended June 30, 2018 Gathering and Processing Transportation (1) and Storage Eliminations Total (In millions) Product sales $ 883 $ 289 $ (228 ) $ 944 Service revenues 349 267 (7 ) 609 Total Revenues 1,232 556 (235 ) 1,553 Cost of natural gas and natural gas liquids (excluding depreciation and amortization shown separately) 769 286 (236 ) 819 Operation and maintenance, General and administrative 152 93 (1 ) 244 Depreciation and amortization 125 67  192 Taxes other than income tax 20 13  33 Operating income $ 166 $ 97 $ 2 $ 265 Total assets as of December 31, 2018 $ 9,874 $ 5,805 $ (3,235 ) $ 12,444 Capital expenditures $ 291 $ 84 $  $ 375 _____________________ (1) See Note 8 for discussion regarding ownership interests in SESH and related equity earnings included in the transportation and storage segment for the three and six months ended June 30, 2019 and 2018 .