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Schedule II. Condensed Financial Information of Registrant (Parent Company) (Schedule of Condensed Financial Information of Registrant, Statements of Operations and Comprehensive Income) (Details) - USD ($) $ in Millions | 3 Months Ended | 12 Months Ended
--- | --- | ---
Dec. 31, 2017 | Sep. 30, 2017 | Jun. 30, 2017 | Mar. 31, 2017 | Dec. 31, 2016 | Sep. 30, 2016 | Jun. 30, 2016 | Mar. 31, 2016 | Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015
Revenues |  |  |  |  |  |  |  |  |  |  |
Net realized investment (losses) gains |  |  |  |  |  |  |  |  | $ 93 | $ 50 | $ (67)
Total revenues | $ 2,448 | $ 2,398 | $ 2,366 | $ 2,330 | $ 2,390 | $ 2,433 | $ 2,348 | $ 2,195 | 9,542 | 9,366 | 9,101
Expenses |  |  |  |  |  |  |  |  |  |  |
Interest |  |  |  |  |  |  |  |  | 161 | 159 | 155
Income tax expense |  |  |  |  |  |  |  |  | (411) | (278) | (70)
Net income | $ 223 | $ 144 | $ 272 | $ 260 | $ 241 | $ 343 | $ 209 | $ 66 | 899 | 859 | 479
Total comprehensive income (loss) |  |  |  |  |  |  |  |  | 1,104 | 1,001 | (236)
Parent Company |  |  |  |  |  |  |  |  |  |  |
Revenues |  |  |  |  |  |  |  |  |  |  |
Net investment income |  |  |  |  |  |  |  |  | 6 | 3 | 1
Net realized investment (losses) gains |  |  |  |  |  |  |  |  | (42) | (7) | 5
Total revenues |  |  |  |  |  |  |  |  | (36) | (4) | 6
Expenses |  |  |  |  |  |  |  |  |  |  |
Administrative and general |  |  |  |  |  |  |  |  | 2 | 1 | 1
Interest |  |  |  |  |  |  |  |  | 152 | 155 | 154
Total expenses |  |  |  |  |  |  |  |  | 154 | 156 | 155
Loss from operations before income taxes and equity in net income of subsidiaries |  |  |  |  |  |  |  |  | (190) | (160) | (149)
Income tax expense |  |  |  |  |  |  |  |  | 57 | 41 | 34
Loss before equity in net income of subsidiaries |  |  |  |  |  |  |  |  | (133) | (119) | (115)
Equity in net income of subsidiaries |  |  |  |  |  |  |  |  | 1,032 | 978 | 594
Net income |  |  |  |  |  |  |  |  | 899 | 859 | 479
Equity in other comprehensive income of subsidiaries |  |  |  |  |  |  |  |  | 205 | 142 | (715)
Total comprehensive income (loss) |  |  |  |  |  |  |  |  | $ 1,104 | $ 1,001 | $ (236)

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