Variable Interest Entities - Narrative (Details) - USD ($)	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Variable Interest Entity [Line Items]
Accrued income and other assets	$ 8,314,000,000		$ 8,601,000,000
Accrued expense and other liabilities	5,008,000,000		5,412,000,000
VIE, assets that can only be used to settle obligations	187,485,000,000		188,281,000,000
VIE, liabilities	172,938,000,000		173,644,000,000
Recurring
Variable Interest Entity [Line Items]
Other investments	64,000,000		63,000,000
Variable Interest Entity, Not Primary Beneficiary
Variable Interest Entity [Line Items]
VIE, assets that can only be used to settle obligations	1,032,000,000		1,149,000,000
VIE, liabilities	1,000,000		1,000,000
Variable Interest Entity, Not Primary Beneficiary | LIHTC
Variable Interest Entity [Line Items]
Accrued income and other assets	2,200,000,000		2,300,000,000
Accrued expense and other liabilities	1,200,000,000		1,400,000,000
VIE, assets that can only be used to settle obligations	8,880,000,000		8,904,000,000
VIE, liabilities	3,841,000,000		3,848,000,000
Variable Interest Entity, Not Primary Beneficiary | NMTC
Variable Interest Entity [Line Items]
Accrued income and other assets	30,000,000		25,000,000
Variable Interest Entity, Not Primary Beneficiary | Other Unconsolidated Variable Interest Entities
Variable Interest Entity [Line Items]
Other investments	606,000,000
Variable Interest Entity, Not Primary Beneficiary | Investments
Variable Interest Entity [Line Items]
Amortization of investment	55,000,000	$ 53,000,000
Tax credit of investment	54,000,000	51,000,000
Other tax benefits	13,000,000	$ 45,000,000
Variable Interest Entity, Primary Beneficiary | Investments
Variable Interest Entity [Line Items]
VIE, assets that can only be used to settle obligations	0		0
VIE, liabilities	0		0
Measured at NAV | Variable Interest Entity, Not Primary Beneficiary | Recurring | Indirect investments
Variable Interest Entity [Line Items]
Other investments	$ 17,000,000		$ 17,000,000