Commitments and Contingencies - Other Commitments (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Dec. 31, 2020
Liquefied Natural Gas Commodities
Loss Contingencies [Line Items]
Other commitments	$ 430	$ 582
Resale and Forward-Dated Resale and Securities Borrowing Agreements
Loss Contingencies [Line Items]
Other commitments	119,000	66,500
Forward-Dated Repurchase and Securities Lending Agreements
Loss Contingencies [Line Items]
Other commitments	60,600	32,100
Auto Loans and Leases
Loss Contingencies [Line Items]
Other commitment, due in next twelve months	$ 3,900	3,900
Other commitment, termination prior notice period	12 months
Residential and Commercial Portfolio Segments \| Residential and Commercial Financing Receivable \| Loan Purchase Commitments
Loss Contingencies [Line Items]
Other commitments	$ 138	93
Commercial \| Loan Purchase Commitments
Loss Contingencies [Line Items]
Other commitments	$ 726	$ 645