Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	1 Months Ended	12 Months Ended
	Mar. 31, 2020	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Changes in Accumulated Other Comprehensive Income (Loss) by Component
Beginning of year balance		$ 75,381	$ 69,701	$ 64,170
Other comprehensive income (loss) before reclassifications, net of tax	$ (5)
Other comprehensive income (loss)		(2,430)	(449)	395
End of year balance		71,315	75,381	69,701
Net unrealized investment gains (losses)
Changes in Accumulated Other Comprehensive Income (Loss) by Component
Beginning of year balance		778	1,214	774
Other comprehensive income (loss) before reclassifications, net of tax		(2,518)	(410)	415
Amounts reclassified from accumulated other comprehensive income (loss), net of tax		239	(26)	25
Other comprehensive income (loss)		(2,279)	(436)	440
End of year balance		(1,501)	778	1,214
OCI before reclassifications, pre-tax		(2,972)	(489)	497
Amounts reclassified, pre-tax		315	(32)	31
Foreign currency translation adjustments
Changes in Accumulated Other Comprehensive Income (Loss) by Component
Beginning of year balance		0	7	4
Other comprehensive income (loss) before reclassifications, net of tax		0	(7)	3
Other comprehensive income (loss)		0	(7)	3
End of year balance		0	0	7
Net cash flow hedges
Changes in Accumulated Other Comprehensive Income (Loss) by Component
Beginning of year balance		222	248	279
Other comprehensive income (loss) before reclassifications, net of tax		28	0	(5)
Amounts reclassified from accumulated other comprehensive income (loss), net of tax		(11)	(26)	(26)
Other comprehensive income (loss)		17	(26)	(31)
End of year balance		239	222	248
OCI before reclassifications, pre-tax		38	0	(7)
Amounts reclassified, pre-tax		(15)	(34)	(35)
Amount expected to be reclassified		11
Pension and other postretirement benefits
Changes in Accumulated Other Comprehensive Income (Loss) by Component
Beginning of year balance		(35)	(55)	(38)
Other comprehensive income (loss) before reclassifications, net of tax		(170)	15	(22)
Amounts reclassified from accumulated other comprehensive income (loss), net of tax		2	5	5
Other comprehensive income (loss)		(168)	20	(17)
End of year balance		(203)	(35)	(55)
OCI before reclassifications, pre-tax		(229)	20	(30)
Amounts reclassified, pre-tax		3	6	7
AOCI Including Portion Attributable to Noncontrolling Interest
Changes in Accumulated Other Comprehensive Income (Loss) by Component
Beginning of year balance		965	1,414	1,019
End of year balance		$ (1,465)	$ 965	$ 1,414