Variable Interest Entities (Aggregate Assets, Liabilities and Maximum Exposure to Loss) (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Variable Interest Entity [Line Items]
Aggregate assets	$ 667,270	$ 549,009	$ 294,000
Aggregate liabilities	611,009	492,949
Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Aggregate assets	1,076	767
Aggregate liabilities	530	344
Maximum exposure to loss	1,126	801
LIHTC investments [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Aggregate assets	915	649
Aggregate liabilities	530	344
Maximum exposure to loss	915	649
Other CRA investments [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Aggregate assets	161	118
Aggregate liabilities	0	0
Maximum exposure to loss	$ 211	$ 152