Accumulated Other Comprehensive Income - Changes in AOCI (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Apr. 01, 2019	Jan. 01, 2019	Apr. 01, 2018	Jan. 01, 2018
Accumulated Other Comprehensive Income (Loss) [Line Items]
Income tax expense (benefit)	$ (261)	$ 116	$ (552)	$ 295
Other comprehensive income (loss)	1,054	(487)	2,232	(1,260)
Adoption of ASU 2016-01								$ (3)
Change in Accumulated Other Comprehensive Income	1,054	(487)	2,232	(1,302)
Unrealized investment gains (losses) on AFS securities
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss), before reclassifications, before tax	1,776	(889)	3,758	(2,171)
DAC, DSI, VOBA, and future policy benefit adjustment on AFS securities
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss), before reclassifications, before tax	(480)	198	(991)	608
Unrealized gains (losses) on AFS securities, including DAC, DSI, VOBA, and future policy benefits
Accumulated Other Comprehensive Income (Loss) [Line Items]
Reclassification adjustment for gains (losses) realized in net income	34	11	27	30
Income tax expense (benefit)	(249)	145	(542)	304
Other comprehensive income (loss)	1,013	(557)	2,198	(1,289)
Noncredit component of OTTI losses on AFS securities
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss), before reclassifications, before tax	0	1	(1)	0
Reclassification adjustment for gains (losses) realized in net income	1	1	1	0
Other comprehensive income (loss)	(1)	0	(2)	0
Unrealized gains (losses) on hedging instruments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss), before reclassifications, before tax	55	101	47	45
Income tax expense (benefit)	(12)	(29)	(10)	(9)
Other comprehensive income (loss)	43	72	37	36
Pension adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss), before reclassifications, before tax	0	0	(1)	3
Foreign currency translation adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss)	$ (1)	$ (2)	$ 0	$ (10)
Accounting Standards Update 2016-01 [Member] | AOCI Including Portion Attributable to Noncontrolling Interest [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Adoption of ASU 2016-01					$ 0	$ 0	$ 0	$ (42)