Equity (Reclassifications Out of Accumulated Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Millions	3 Months Ended				6 Months Ended
	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2020	Jun. 30, 2019
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net investment gains (losses)	$ (33)		$ 56		$ (52)	$ 46
Net investment income	635		918		1,531	1,706
Net derivative gains (losses)	(2,650)		108		4,097	(1,202)
Income (loss) before provision for income tax	(2,549)		439		3,555	(536)
Income tax (expense) benefit	552		(76)		(713)	145
Net income (loss)	(1,997)	$ 4,839	363	$ (754)	2,842	(391)
Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net income (loss)	(15)		59		(5)	57
Reclassification out of Accumulated Other Comprehensive Income | Net unrealized investment gains (losses):
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net investment gains (losses)	(19)		74		(7)	50
Net derivative gains (losses)	(4)		(23)		(6)	(27)
Income (loss) before provision for income tax	(23)		51		(13)	23
Income tax (expense) benefit	5		(11)		3	(5)
Net income (loss)	(18)		40		(10)	18
Reclassification out of Accumulated Other Comprehensive Income | Unrealized gains (losses) on derivatives - cash flow hedges:
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income (loss) before provision for income tax	4		23		6	49
Income tax (expense) benefit	(1)		(4)		(1)	(10)
Net income (loss)	3		19		5	39
Reclassification out of Accumulated Other Comprehensive Income | Unrealized gains (losses) on derivatives - cash flow hedges: | Interest rate swaps
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net investment income	0		0		1	1
Net derivative gains (losses)	0		6		1	28
Reclassification out of Accumulated Other Comprehensive Income | Unrealized gains (losses) on derivatives - cash flow hedges: | Foreign currency swaps
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net derivative gains (losses)	$ 4		$ 17		$ 4	$ 20