Fair Value - Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis (Details) - USD ($) $ in Millions	Jun. 30, 2022	Dec. 31, 2021
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investment securities available for sale	$ 9,210	$ 9,203
Marketable equity securities	94	98
Fair value of derivative financial instruments	80	3
Fair value of derivative financial instruments	308	1
Fair Value, Recurring
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investment securities available for sale	9,210	9,203
Marketable equity securities	94	98
Loans held for sale	22	99
Fair value of derivative financial instruments	80
Fair value of derivative financial instruments	308
Fair Value, Recurring \| Interest rate contracts
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair value of derivative financial instruments	76
Fair value of derivative financial instruments	305
Fair Value, Recurring \| Other derivative
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair value of derivative financial instruments	4
Fair value of derivative financial instruments	3
Fair Value, Recurring \| Level 1
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investment securities available for sale	0	0
Marketable equity securities	32	34
Loans held for sale	0	0
Fair value of derivative financial instruments	0
Fair value of derivative financial instruments	0
Fair Value, Recurring \| Level 1 \| Interest rate contracts
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair value of derivative financial instruments	0
Fair value of derivative financial instruments	0
Fair Value, Recurring \| Level 1 \| Other derivative
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair value of derivative financial instruments	0
Fair value of derivative financial instruments	0
Fair Value, Recurring \| Level 2
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investment securities available for sale	9,030	8,996
Marketable equity securities	62	64
Loans held for sale	22	99
Fair value of derivative financial instruments	79
Fair value of derivative financial instruments	308
Fair Value, Recurring \| Level 2 \| Interest rate contracts
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair value of derivative financial instruments	75
Fair value of derivative financial instruments	305
Fair Value, Recurring \| Level 2 \| Other derivative
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair value of derivative financial instruments	4
Fair value of derivative financial instruments	3
Fair Value, Recurring \| Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investment securities available for sale	180	207
Marketable equity securities	0	0
Loans held for sale	0	0
Fair value of derivative financial instruments	1
Fair value of derivative financial instruments	0
Fair Value, Recurring \| Level 3 \| Interest rate contracts
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair value of derivative financial instruments	1
Fair value of derivative financial instruments	0
Fair Value, Recurring \| Level 3 \| Other derivative
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair value of derivative financial instruments	0
Fair value of derivative financial instruments	0
Fair Value, Recurring \| U.S. Treasury
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investment securities available for sale	1,903	2,005
Fair Value, Recurring \| U.S. Treasury \| Level 1
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investment securities available for sale	0	0
Fair Value, Recurring \| U.S. Treasury \| Level 2
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investment securities available for sale	1,903	2,005
Fair Value, Recurring \| U.S. Treasury \| Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investment securities available for sale	0	0
Fair Value, Recurring \| Government agency
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investment securities available for sale	190	221
Fair Value, Recurring \| Government agency \| Level 1
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investment securities available for sale	0	0
Fair Value, Recurring \| Government agency \| Level 2
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investment securities available for sale	190	221
Fair Value, Recurring \| Government agency \| Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investment securities available for sale	0	0
Fair Value, Recurring \| Residential mortgage-backed securities
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investment securities available for sale	5,020	4,729
Fair Value, Recurring \| Residential mortgage-backed securities \| Level 1
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investment securities available for sale	0	0
Fair Value, Recurring \| Residential mortgage-backed securities \| Level 2
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investment securities available for sale	5,020	4,729
Fair Value, Recurring \| Residential mortgage-backed securities \| Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investment securities available for sale	0	0
Fair Value, Recurring \| Commercial mortgage-backed securities
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investment securities available for sale	1,527	1,640
Fair Value, Recurring \| Commercial mortgage-backed securities \| Level 1
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investment securities available for sale	0	0
Fair Value, Recurring \| Commercial mortgage-backed securities \| Level 2
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investment securities available for sale	1,527	1,640
Fair Value, Recurring \| Commercial mortgage-backed securities \| Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investment securities available for sale	0	0
Fair Value, Recurring \| Corporate bonds
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investment securities available for sale	570	608
Fair Value, Recurring \| Corporate bonds \| Level 1
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investment securities available for sale	0	0
Fair Value, Recurring \| Corporate bonds \| Level 2
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investment securities available for sale	390	401
Fair Value, Recurring \| Corporate bonds \| Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Investment securities available for sale	$ 180	$ 207

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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