Accumulated Other Comprehensive Income - Activity in AOCI (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss), pre-tax activity	$ (2,019)	$ 239	$ (5,011)	$ (813)
Other comprehensive income (loss), tax effect	471	(57)	1,160	186
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance	20,177	22,595	22,210	23,111
Other comprehensive (loss) income, net of tax	(1,548)	182	(3,851)	(627)
Balance	18,970	22,926	18,970	22,926
AOCI
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance	(1,096)	1,792	1,207	2,601
Other comprehensive (loss) income, net of tax	(1,548)	182	(3,851)	(627)
Balance	(2,644)	1,974	(2,644)	1,974
Available-for-sale debt securities
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss) before reclassifications, pre-tax activity	(1,964)	306	(4,469)	(609)
Other comprehensive income (loss), before reclassifications, tax effect	458	(71)	1,034	143
Other comprehensive income (loss), before reclassifications, net activity	(1,506)	235	(3,435)	(466)
Reclassification adjustment, pre-tax activity	0	(7)	(3)	9
Reclassification adjustment, tax effect	0	2	1	(2)
Reclassification adjustment, net activity	0	(5)	(2)	7
Other comprehensive income (loss), pre-tax activity	(1,964)	299	(4,472)	(600)
Other comprehensive income (loss), tax effect	458	(69)	1,035	141
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance	(1,040)	1,242	891	1,931
Other comprehensive (loss) income, net of tax	(1,506)	230	(3,437)	(459)
Balance	(2,546)	1,472	(2,546)	1,472
Cash flow hedge derivatives
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss) before reclassifications, pre-tax activity	2	11	(405)	(70)
Other comprehensive income (loss), before reclassifications, tax effect	0	(2)	95	15
Other comprehensive income (loss), before reclassifications, net activity	2	9	(310)	(55)
Reclassification adjustment, pre-tax activity	(58)	(73)	(136)	(146)
Reclassification adjustment, tax effect	13	15	30	31
Reclassification adjustment, net activity	(45)	(58)	(106)	(115)
Other comprehensive income (loss), pre-tax activity	(56)	(62)	(541)	(216)
Other comprehensive income (loss), tax effect	13	13	125	46
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance	(20)	597	353	718
Other comprehensive (loss) income, net of tax	(43)	(49)	(416)	(170)
Balance	(63)	548	(63)	548
Defined benefit pension plants, net
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss) before reclassifications, pre-tax activity	(1)	(1)	(1)	(1)
Other comprehensive income (loss), before reclassifications, tax effect	0	0	0	0
Other comprehensive income (loss), before reclassifications, net activity	(1)	(1)	(1)
Reclassification adjustment, pre-tax activity	2	3	3	4
Reclassification adjustment, tax effect	0	(1)	0	(1)
Reclassification adjustment, net activity	2	2	3	3
Other comprehensive income (loss), pre-tax activity	1	2	2	3
Other comprehensive income (loss), tax effect	0	(1)	0	(1)
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance	(32)	(43)	(33)	(44)
Other comprehensive (loss) income, net of tax	1	1	2	2
Balance	(31)	(42)	(31)	(42)
Other
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss), pre-tax activity	0	0	0	0
Other comprehensive income (loss), tax effect	0	0	0	0
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance	(4)	(4)	(4)	(4)
Other comprehensive (loss) income, net of tax	0	0	0	0
Balance	$ (4)	$ (4)	$ (4)	$ (4)