Variable Interest Entities - Additional Information (Details) - USD ($)	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Variable Interest Entity [Line Items]
VIE, assets that can only be used to settle obligations	$ 187,035,000,000		$ 170,336,000,000
VIE, liabilities	169,525,000,000		152,355,000,000
Recurring
Variable Interest Entity [Line Items]
Other investments	80,000,000		81,000,000
Variable Interest Entity, Not Primary Beneficiary
Variable Interest Entity [Line Items]
VIE, assets that can only be used to settle obligations	3,166,000,000		351,000,000
VIE, liabilities	1,000,000		1,000,000
Tax credit of investment		$ 135,000,000
Variable Interest Entity, Not Primary Beneficiary | Qualified affordable housing projects investment
Variable Interest Entity [Line Items]
VIE, liabilities	608,000,000		484,000,000
Variable Interest Entity, Not Primary Beneficiary | Other Unconsolidated Variable Interest Entities
Variable Interest Entity [Line Items]
Other investments	2,800,000,000
Variable Interest Entity, Not Primary Beneficiary | Accrued Income And Other Assets
Variable Interest Entity [Line Items]
VIE, assets that can only be used to settle obligations	1,500,000,000		1,400,000,000
Variable Interest Entity, Not Primary Beneficiary | Investments
Variable Interest Entity [Line Items]
Amortization of investment	147,000,000	$ 137,000,000
Tax credit of investment	139,000,000
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 | Principal Investments, Indirect
Variable Interest Entity [Line Items]
Other investments	$ 48,000,000		$ 53,000,000