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)	$ 231		$ 61		$ (57)	$ 76
Net derivative gains (losses)	(710)		724		3,491	839
Net investment income	4,087		4,693		7,148	9,601
Other expenses	2,983		3,390		6,256	6,615
Income (loss) from continuing operations before provision for income tax	197		2,297		5,840	4,041
Income tax (expense) benefit	(47)		(551)		(1,289)	(910)
Net income (loss)	150	$ 4,401	1,746	$ 1,385	4,551	3,131
Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net income (loss)	297		152		77	143
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)	51		140		255	116
Net derivative gains (losses)	(6)		(6)		(12)	16
Net investment income	1		(7)		(10)	(3)
Income (loss) from continuing operations before provision for income tax	46		127		233	129
Income tax (expense) benefit	2		(30)		(46)	(30)
Net income (loss)	48		97		187	99
Reclassification out of Accumulated Other Comprehensive Income | Unrealized Gains (Losses) on Derivatives
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income (loss) from continuing operations before provision for income tax	340		92		(98)	116
Income tax (expense) benefit	(74)		(14)		22	(26)
Net income (loss)	266		78		(76)	90
Reclassification out of Accumulated Other Comprehensive Income | Unrealized Gains (Losses) on Derivatives | Interest Rate Contract
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net investment gains (losses)	42		4		48	(2)
Net investment income	9		6		15	11
Other expenses	0		0		1	1
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)	287		83		(164)	108
Net investment income	1		(1)		1	(3)
Other expenses	1		1		1	1
Reclassification out of Accumulated Other Comprehensive Income | Unrealized Gains (Losses) on Derivatives | Credit
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net investment gains (losses)	0		(1)		0	0
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)	(26)		(36)		(52)	(72)
Amortization of prior service (costs) credit	4		6		9	13
Income (loss) from continuing operations before provision for income tax	(22)		(30)		(43)	(59)
Income tax (expense) benefit	5		7		9	13
Net income (loss)	$ (17)		$ (23)		$ (34)	$ (46)