Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	3 Months Ended						9 Months Ended
	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2022	Sep. 30, 2021
Changes in Accumulated Other Comprehensive Income (Loss) by Component
Balance at beginning of period	$ 75,506	$ 74,140	$ 75,381	$ 73,565	$ 71,164	$ 69,701	$ 75,381	$ 69,701
Other comprehensive loss	(621)	(798)	(1,155)	(93)	148	(392)	(2,574)	(337)
Balance at end of period	71,011	75,506	74,140	74,618	73,565	71,164	71,011	74,618
Net unrealized investment gains (losses)
Changes in Accumulated Other Comprehensive Income (Loss) by Component
Balance at beginning of period	(1,190)		778	977		1,214	778	1,214
Other comprehensive income (loss) before reclassifications, net of tax	(711)			(61)			(2,809)	(297)
Amounts reclassified from accumulated other comprehensive income (loss), net of tax	88			(12)			218	(13)
Other comprehensive loss	(623)			(73)			(2,591)	(310)
Balance at end of period	(1,813)	(1,190)		904	977		(1,813)	904
OCI before reclassifications, pre-tax	(796)			(73)			(3,306)	(346)
Amounts reclassified, pre-tax	99			(14)			253	(15)
Foreign currency translation adjustments
Changes in Accumulated Other Comprehensive Income (Loss) by Component
Balance at beginning of period	2		0	6		7	0	7
Other comprehensive income (loss) before reclassifications, net of tax	(7)			(5)			(5)	(6)
Other comprehensive loss	(7)			(5)			(5)	(6)
Balance at end of period	(5)	2		1	6		(5)	1
Net cash flow hedges
Changes in Accumulated Other Comprehensive Income (Loss) by Component
Balance at beginning of period	234		222	241		248	222	248
Other comprehensive income (loss) before reclassifications, net of tax	10			0			28	0
Amounts reclassified from accumulated other comprehensive income (loss), net of tax	(2)			(15)			(8)	(22)
Other comprehensive loss	8			(15)			20	(22)
Balance at end of period	242	234		226	241		242	226
OCI before reclassifications, pre-tax	13			0			37	0
Amounts reclassified, pre-tax	(2)			(20)			(10)	(29)
Amount expected to be reclassified	11						11
Pension and other postretirement benefits
Changes in Accumulated Other Comprehensive Income (Loss) by Component
Balance at beginning of period	(34)		(35)	(54)		(55)	(35)	(55)
Amounts reclassified from accumulated other comprehensive income (loss), net of tax	1			0			2	1
Other comprehensive loss	1			0			2	1
Balance at end of period	(33)	(34)		(54)	(54)		(33)	(54)
Amounts reclassified, pre-tax	1			0			2	1
AOCI Including Portion Attributable to Noncontrolling Interest
Changes in Accumulated Other Comprehensive Income (Loss) by Component
Balance at beginning of period	(988)		$ 965	1,170		$ 1,414	965	1,414
Balance at end of period	$ (1,609)	$ (988)		$ 1,077	$ 1,170		$ (1,609)	$ 1,077