Other Comprehensive Income (Details) - USD ($) $ in Millions	3 Months Ended				6 Months Ended
	Jun. 30, 2022	Mar. 31, 2022	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2022	Jun. 30, 2021
Changes in Accumulated Other Comprehensive Income (Loss) by Component
Balance at beginning of period	$ 74,140	$ 75,381	$ 71,164	$ 69,701	$ 75,381	$ 69,701
Other comprehensive income (loss)	(798)	(1,155)	148	(392)	(1,953)	(244)
Balance at end of period	75,506	74,140	73,565	71,164	75,506	73,565
Net unrealized investment gains (losses)
Changes in Accumulated Other Comprehensive Income (Loss) by Component
Balance at beginning of period	(377)	778	828	1,214	778	1,214
Other comprehensive income (loss) before reclassifications, net of tax	(868)		164		(2,098)	(236)
Amounts reclassified from accumulated other comprehensive income, net of tax	55		(15)		130	(1)
Other comprehensive income (loss)	(813)		149		(1,968)	(237)
Balance at end of period	(1,190)	(377)	977	828	(1,190)	977
OCI before reclassifications, pre-tax	(1,105)		214		(2,510)	(273)
Amounts reclassified, pre-tax	77		(18)		154	(1)
Foreign currency translation adjustments
Changes in Accumulated Other Comprehensive Income (Loss) by Component
Balance at beginning of period	3	0	5	7	0	7
Other comprehensive income (loss) before reclassifications, net of tax	(1)		1		2	(1)
Other comprehensive income (loss)	(1)		1		2	(1)
Balance at end of period	2	3	6	5	2	6
Net cash flow hedges
Changes in Accumulated Other Comprehensive Income (Loss) by Component
Balance at beginning of period	219	222	244	248	222	248
Other comprehensive income (loss) before reclassifications, net of tax	18		0		18	0
Amounts reclassified from accumulated other comprehensive income, net of tax	(3)		(3)		(6)	(7)
Other comprehensive income (loss)	15		(3)		12	(7)
Balance at end of period	234	219	241	244	234	241
OCI before reclassifications, pre-tax	24		0		24	0
Amounts reclassified, pre-tax	(4)		(4)		(8)	(9)
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	(35)	(35)	(55)	(55)	(35)	(55)
Amounts reclassified from accumulated other comprehensive income, net of tax	1		1		1	1
Other comprehensive income (loss)	1		1		1	1
Balance at end of period	(34)	(35)	(54)	(55)	(34)	(54)
Amounts reclassified, pre-tax	1		1		1	1
AOCI Including Portion Attributable to Noncontrolling Interest
Changes in Accumulated Other Comprehensive Income (Loss) by Component
Balance at beginning of period	(190)	965	1,022	1,414	965	1,414
Balance at end of period	$ (988)	$ (190)	$ 1,170	$ 1,022	$ (988)	$ 1,170