Schedule II. Condensed Financial Information of Registrant (Parent Company) (Schedule of Condensed Financial Information of Registrant, Statements of Operations and Comprehensive Income (Loss)) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenues
Net investment income									$ 2,118	$ 1,817	$ 2,034
Net investment losses									29	(52)	93
Total revenues	$ 2,777	$ 2,685	$ 2,610	$ 2,695	$ 2,403	$ 2,622	$ 2,574	$ 2,535	10,767	10,134	9,542
Expenses
Interest									131	138	161
Income tax benefit									(223)	(151)	(411)
Net income	$ 273	$ 107	$ 278	$ 342	$ (84)	$ 336	$ 270	$ 291	1,000	813	899
Total comprehensive income (loss)									1,929	(81)	1,104
Parent Company
Revenues
Net investment income									13	10	6
Net investment losses									(21)	0	(42)
Total revenues									(8)	10	(36)
Expenses
Administrative and general									1	1	2
Interest									131	135	152
Total expenses									132	136	154
Loss from operations before income taxes and equity in net income of subsidiaries									(140)	(126)	(190)
Income tax benefit									21	9	57
Loss before equity in net income of subsidiaries									(119)	(117)	(133)
Equity in net income of subsidiaries									1,119	930	1,032
Net income									1,000	813	899
Equity in other comprehensive income (loss) of subsidiaries									929	(894)	205
Total comprehensive income (loss)									$ 1,929	$ (81)	$ 1,104