Derivative Financial Instruments - Fair Value Hedges Basis Adjusments (Details) - Fair Value Hedges - USD ($) $ in Millions		Dec. 31, 2021	Dec. 31, 2020
AFS securities (1)
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Hedged Asset / Liability Basis	[1]	$ 108,758	$ 100,988
AFS securities (1) | Items Currently Designated
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Hedge Basis Adjustment		(400)	(33)
AFS securities (1) | Discontinued Hedges
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Hedge Basis Adjustment		(150)	50
Loans and leases
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Hedged Asset / Liability Basis		382	470
Loans and leases | Items Currently Designated
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Hedge Basis Adjustment		0	0
Loans and leases | Discontinued Hedges
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Hedge Basis Adjustment		12	18
Long-term debt
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Hedged Asset / Liability Basis		27,361	27,725
Long-term debt | Items Currently Designated
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Hedge Basis Adjustment		(137)	0
Long-term debt | Discontinued Hedges
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Hedge Basis Adjustment		$ 629	$ 930

[1] The amortized cost of AFS securities was $110.6 billion at December 31, 2021 and $99.4 billion at December 31, 2020.