Equity (Reclassifications Out of Accumulated Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net investment gains (losses)	$ 30	$ 88			$ (96)	$ 100
Net derivative gains (losses)	(549)	732			2,213	630
Net investment income	2,774	2,749			7,423	8,188
Income (loss) before provision for income tax	412	1,572			4,293	3,303
Income tax (expense) benefit	(7)	(233)			(626)	(389)
Net income (loss)	405	1,339	$ 3,262	$ 1,575	3,667	2,914
Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net income (loss)	318	(277)			151	(215)
Reclassification out of Accumulated Other Comprehensive Income | Unrealized Investment Gains (Losses), Net of Related Offsets
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net investment gains (losses)	11	7			(47)	48
Net derivative gains (losses)	(4)	(6)			(12)	(45)
Net investment income	(6)	(8)			(14)	(8)
Income (loss) before provision for income tax	1	(7)			(73)	(5)
Income tax (expense) benefit	(10)	1			5	1
Net income (loss)	(9)	(6)			(68)	(4)
Reclassification out of Accumulated Other Comprehensive Income | Unrealized Gains (Losses) on Derivatives
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income (loss) before provision for income tax	427	(339)			305	(250)
Income tax (expense) benefit	(90)	72			(64)	53
Net income (loss)	337	(267)			241	(197)
Reclassification out of Accumulated Other Comprehensive Income | Unrealized Gains (Losses) on Derivatives | Interest rate derivatives
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net investment gains (losses)	10	0			58	(1)
Net investment income	9	5			24	16
Reclassification out of Accumulated Other Comprehensive Income | Unrealized Gains (Losses) on Derivatives | Foreign currency swaps
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net investment gains (losses)	406	(344)			221	(263)
Net investment income	2	0			2	(2)
Reclassification out of Accumulated Other Comprehensive Income | Defined Benefit Plans Adjustment
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Amortization of net actuarial gains (losses)	(14)	(6)			(30)	(20)
Amortization of prior service (costs) credit	1	1			2	2
Income (loss) before provision for income tax	(13)	(5)			(28)	(18)
Income tax (expense) benefit	3	1			6	4
Net income (loss)	$ (10)	$ (4)			$ (22)	$ (14)