Debt (Pledged Assets Related to Secured Borrowings and Repurchase Agreement) (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Pledged Assets related to secured borrowings [Line Items]
Pledged assets, restricted as collateral	$ 39,265	$ 27,420
Secured debt	10,124	7,619
Short-term borrowings	2,399	0
Pledged assets for Federal Home Loan Bank
Pledged Assets related to secured borrowings [Line Items]
Pledged assets, restricted as collateral	27,000	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
Investment securities
Pledged Assets related to secured borrowings [Line Items]
Pledged assets, restricted as collateral	3,525	0
Consumer | Consumer mortgage
Pledged Assets related to secured borrowings [Line Items]
Pledged assets, restricted as collateral	19,771	17,941
Consumer | Automotive
Pledged Assets related to secured borrowings [Line Items]
Pledged assets, restricted as collateral	11,759	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	$ 4,210	$ 10