Commitments and Contingencies - Other Commitments (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2020	Dec. 31, 2019
Liquefied Natural Gas Commodities
Loss Contingencies [Line Items]
Other commitments	$ 498	$ 830
Resale and Forward-Dated Resale and Securities Borrowing Agreements
Loss Contingencies [Line Items]
Other commitments	144,300	97,200
Forward-Dated Repurchase and Securities Lending Agreements
Loss Contingencies [Line Items]
Other commitments	45,500	24,900
Auto Loans and Leases
Loss Contingencies [Line Items]
Other commitment, due in next twelve months	$ 3,500	3,300
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	$ 169	86
Commercial portfolio \| Loan Purchase Commitments
Loss Contingencies [Line Items]
Other commitments	$ 430	$ 1,100