Debt (Pledged Assets Related to Secured Borrowings and Repurchase Agreement) (Details) - USD ($) $ in Millions	Sep. 30, 2022	Dec. 31, 2021
Pledged Assets related to secured borrowings [Line Items]
Pledged assets, restricted as collateral	$ 38,170	$ 27,420
Secured debt	14,627	7,619
Short-term borrowings	7,200	0
Investment securities
Pledged Assets related to secured borrowings [Line Items]
Pledged assets, restricted as collateral	3,092	0
Pledged assets for Federal Home Loan Bank
Pledged Assets related to secured borrowings [Line Items]
Pledged assets, restricted as collateral	27,200	18,000
Pledged assets for Federal Reserve Bank
Pledged Assets related to secured borrowings [Line Items]
Pledged assets, restricted as collateral	2,400	2,400
Consumer | Consumer mortgage
Pledged Assets related to secured borrowings [Line Items]
Pledged assets, restricted as collateral	20,055	17,941
Consumer | Consumer automotive
Pledged Assets related to secured borrowings [Line Items]
Pledged assets, restricted as collateral	10,926	9,122
Consumer | Credit card receivables
Pledged Assets related to secured borrowings [Line Items]
Pledged assets, restricted as collateral	0	347
Commercial
Pledged Assets related to secured borrowings [Line Items]
Pledged assets, restricted as collateral	$ 4,097	$ 10