Variable Interest Entities - Additional Information (Details) - USD ($)	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Variable Interest Entity [Line Items]
VIE, assets that can only be used to settle obligations	$ 171,192,000,000		$ 144,988,000,000
VIE, liabilities	153,650,000,000		127,950,000,000
Recurring
Variable Interest Entity [Line Items]
Other investments	78,000,000		90,000,000
Variable Interest Entity, Primary Beneficiary | Investments
Variable Interest Entity [Line Items]
VIE, assets that can only be used to settle obligations			0
VIE, liabilities			0
Variable Interest Entity, Not Primary Beneficiary
Variable Interest Entity [Line Items]
VIE, assets that can only be used to settle obligations	300,000,000		282,000,000
VIE, liabilities	1,000,000		1,000,000
Variable Interest Entity, Not Primary Beneficiary | LIHTC investments
Variable Interest Entity [Line Items]
VIE, assets that can only be used to settle obligations	6,300,000,000		6,405,000,000
VIE, liabilities	2,534,000,000		2,526,000,000
Tax credit of investment		$ 92,000,000
Variable Interest Entity, Not Primary Beneficiary | LIHTC investments | Qualified affordable housing projects investment [Member]
Variable Interest Entity [Line Items]
VIE, liabilities	465,000,000		546,000,000
Variable Interest Entity, Not Primary Beneficiary | LIHTC investments | Accrued Income And Other Assets
Variable Interest Entity [Line Items]
VIE, assets that can only be used to settle obligations	1,400,000,000		1,500,000,000
Variable Interest Entity, Not Primary Beneficiary | LIHTC investments | Investments
Variable Interest Entity [Line Items]
Amortization of investment	97,000,000	$ 89,000,000
Tax credit of investment	90,000,000
Variable Interest Entity, Not Primary Beneficiary | Measured at NAV | Recurring | Principal Investments, Indirect
Variable Interest Entity [Line Items]
Other investments	56,000,000		$ 68,000,000
Variable Interest Entity, Primary Beneficiary | Investments
Variable Interest Entity [Line Items]
VIE, assets that can only be used to settle obligations	0
VIE, liabilities	$ 0