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Investment Securities - Components of Held-to-Maturity Investment Securities (Details) - USD ($) $ in Millions	Sep. 30, 2022	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Dec. 31, 2020
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	$ 93,292	$ 98,202
Unrealized Gains	0	368
Unrealized Losses	(15,922)	(1,343)
Fair Value	77,370	97,227
Held-to-maturity securities, allowance for credit losses	6	7	$ 6	$ 5	$ 1
U.S. agency debentures
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	486	609
Unrealized Gains	0	8
Unrealized Losses	(53)	(2)
Fair Value	433	615
Held-to-maturity securities, allowance for credit losses	0	0
Agency-issued MBS
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	59,200	64,439
Unrealized Gains	0	124
Unrealized Losses	(10,017)	(887)
Fair Value	49,183	63,676
Held-to-maturity securities, allowance for credit losses	0	0
Agency-issued CMO \| Fixed rate
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	10,741	10,226
Unrealized Gains	0	9
Unrealized Losses	(1,813)	(145)
Fair Value	8,928	10,090
Held-to-maturity securities, allowance for credit losses	0	0
Agency-issued CMO \| Variable rate
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	83	100
Unrealized Gains	0	1
Unrealized Losses	(1)	0
Fair Value	82	101
Held-to-maturity securities, allowance for credit losses	0	0
Agency-issued CMBS
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	14,644	14,959
Unrealized Gains	0	39
Unrealized Losses	(2,304)	(277)
Fair Value	12,340	14,721
Held-to-maturity securities, allowance for credit losses	0	0
Municipal bonds and notes
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	7,429	7,157
Unrealized Gains	0	185
Unrealized Losses	(1,612)	(27)
Fair Value	5,817	7,315
Held-to-maturity securities, allowance for credit losses	1	1
Corporate bonds
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	709	712
Unrealized Gains	0	2
Unrealized Losses	(122)	(5)
Fair Value	587	709
Held-to-maturity securities, allowance for credit losses	$ 5	$ 6