Fair Value, Assets and Liabilities, Fair Value on a Nonrecurring Basis (Details) - Nonrecurring [Member] - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held for sale	$ 4,547	$ 5,318
Loans	421	856
Other assets	1,848	1,548
Total assets at fair value on a nonrecurring basis	9,214	15,316
Nonmarketable equity securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nonmarketable equity securities	2,323	7,027
Total Commercial [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans	29	476
Mortgage servicing rights	75	567
Total Consumer [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans	392	380
Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held for sale	3,125	3,911
Loans	421	856
Other assets	1,746	1,373
Total assets at fair value on a nonrecurring basis	6,567	12,402
Level 2 [Member] | Nonmarketable equity securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nonmarketable equity securities	1,275	6,262
Level 2 [Member] | Total Commercial [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans	29	476
Mortgage servicing rights	0	0
Level 2 [Member] | Total Consumer [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans	392	380
Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held for sale	1,422	1,407
Loans	0	0
Other assets	102	175
Total assets at fair value on a nonrecurring basis	2,647	2,914
Level 3 [Member] | Nonmarketable equity securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Nonmarketable equity securities	1,048	765
Level 3 [Member] | Total Commercial [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans	0	0
Mortgage servicing rights	75	567
Level 3 [Member] | Total Consumer [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans	$ 0	$ 0