Investment Securities - Schedule of Amortized Cost and Fair Value of Investment Securities (Details) - USD ($) $ in Millions	Sep. 30, 2022	Dec. 31, 2021
Investment securities available for sale
Investment securities available for sale, cost	$ 10,083	$ 9,215
Investment securities available for sale, gross unrealized gains	0	45
Investment securities available for sale, gross unrealized losses	(995)	(57)
Investment securities available for sale	9,088	9,203
Investment in marketable equity securities
Investment in marketable equity securities at cost	73	73
Investment in marketable equity, gross unrealized gains	20	25
Investment in marketable equity, gross unrealized losses	(1)	0
Investment in marketable equity, fair value	92	98
Investment securities held to maturity
Investment securities held to maturity, cost	9,661	3,809
Investment securities held to maturity, gross unrealized gains	0	6
Investment securities held to maturity, gross unrealized losses	(1,495)	(56)
Investment securities held to maturity, cost, fair value	8,166	3,759
Total investment securities
Total investment securities, amortized cost	19,817	13,097
Total investment securities, gross unrealized gains	20	76
Total investment securities, gross unrealized losses	(2,491)	(113)
Total investment securities, fair value	17,346	13,060
U.S. Treasury
Investment securities available for sale
Investment securities available for sale, cost	2,047	2,007
Investment securities available for sale, gross unrealized gains	0	0
Investment securities available for sale, gross unrealized losses	(147)	(2)
Investment securities available for sale	1,900	2,005
Investment securities held to maturity
Investment securities held to maturity, cost	473
Investment securities held to maturity, gross unrealized gains	0
Investment securities held to maturity, gross unrealized losses	(54)
Investment securities held to maturity, cost, fair value	419
Government agency
Investment securities available for sale
Investment securities available for sale, cost	175	221
Investment securities available for sale, gross unrealized gains	0	1
Investment securities available for sale, gross unrealized losses	(2)	(1)
Investment securities available for sale	173	221
Investment securities held to maturity
Investment securities held to maturity, cost	1,546
Investment securities held to maturity, gross unrealized gains	0
Investment securities held to maturity, gross unrealized losses	(196)
Investment securities held to maturity, cost, fair value	1,350
Residential mortgage-backed securities
Investment securities available for sale
Investment securities available for sale, cost	5,450	4,757
Investment securities available for sale, gross unrealized gains	0	8
Investment securities available for sale, gross unrealized losses	(666)	(36)
Investment securities available for sale	4,784	4,729
Investment securities held to maturity
Investment securities held to maturity, cost	4,510	2,322
Investment securities held to maturity, gross unrealized gains	0	6
Investment securities held to maturity, gross unrealized losses	(765)	(22)
Investment securities held to maturity, cost, fair value	3,745	2,306
Commercial mortgage-backed securities
Investment securities available for sale
Investment securities available for sale, cost	1,828	1,648
Investment securities available for sale, gross unrealized gains	0	9
Investment securities available for sale, gross unrealized losses	(155)	(17)
Investment securities available for sale	1,673	1,640
Investment securities held to maturity
Investment securities held to maturity, cost	2,834	1,485
Investment securities held to maturity, gross unrealized gains	0	0
Investment securities held to maturity, gross unrealized losses	(437)	(34)
Investment securities held to maturity, cost, fair value	2,397	1,451
Corporate bonds
Investment securities available for sale
Investment securities available for sale, cost	583	582
Investment securities available for sale, gross unrealized gains	0	27
Investment securities available for sale, gross unrealized losses	(25)	(1)
Investment securities available for sale	558	608
Supranational securities
Investment securities held to maturity
Investment securities held to maturity, cost	295
Investment securities held to maturity, gross unrealized gains	0
Investment securities held to maturity, gross unrealized losses	(43)
Investment securities held to maturity, cost, fair value	252
Other
Investment securities held to maturity
Investment securities held to maturity, cost	3	2
Investment securities held to maturity, gross unrealized gains	0	0
Investment securities held to maturity, gross unrealized losses	0	0
Investment securities held to maturity, cost, fair value	$ 3	$ 2

Equity Securities FV-NI, Accumulated Gross Unrealized Gain, before Tax

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Equity Securities FV-NI, Accumulated Gross Unrealized Loss, before Tax

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Investments, Accumulated Unrecognized Gain

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Investments, Amortized Cost

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Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amount, before tax, of unrealized loss in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amortized cost excluding accrued interest, after allowance for credit loss, of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amount excluding accrued interest, of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amount excluding accrued interest, before allowance for credit loss, of investment in debt security measured at amortized cost (held-to-maturity).

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Amount of investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI), classified as current.

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Cost of investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI). Excludes equity method investment and investment in equity security without readily determinable fair value.

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Amount of accumulated unrecognized gain on investment in debt security measured at amortized cost (held-to-maturity).

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Amount of accumulated unrealized loss on investment in debt security measured at amortized cost (held-to-maturity).

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Fair value of investment in debt security measured at amortized cost (held-to-maturity).

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Fair value portion of investment securities, including, but not limited to, marketable securities, derivative financial instruments, and investments accounted for under the equity method.

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