Fair Value (Schedule of Assets with Fair Value Changes on Nonrecurring Basis) (Details) - USD ($) $ in Millions	Jun. 30, 2021	Dec. 31, 2020
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets, fair value	$ 19,470	$ 17,163
Fair Value, Nonrecurring
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets, fair value	9	16
Private equity investments | Fair Value, Nonrecurring
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets, fair value	0	1
Collateral-dependent loans | Fair Value, Nonrecurring
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets, fair value	9	14
Other real estate owned | Fair Value, Nonrecurring
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets, fair value	0	1
Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets, fair value	359	427
Level 1 | Fair Value, Nonrecurring
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets, fair value	0	0
Level 1 | Private equity investments | Fair Value, Nonrecurring
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets, fair value	0	0
Level 1 | Collateral-dependent loans | Fair Value, Nonrecurring
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets, fair value	0	0
Level 1 | Other real estate owned | Fair Value, Nonrecurring
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets, fair value	0	0
Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets, fair value	19,024	16,640
Level 2 | Fair Value, Nonrecurring
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets, fair value	9	15
Level 2 | Private equity investments | Fair Value, Nonrecurring
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets, fair value	0	0
Level 2 | Collateral-dependent loans | Fair Value, Nonrecurring
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets, fair value	9	14
Level 2 | Other real estate owned | Fair Value, Nonrecurring
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets, fair value	0	1
Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets, fair value	87	96
Level 3 | Fair Value, Nonrecurring
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets, fair value	0	1
Level 3 | Private equity investments | Fair Value, Nonrecurring
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets, fair value	0	1
Level 3 | Collateral-dependent loans | Fair Value, Nonrecurring
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets, fair value	0	0
Level 3 | Other real estate owned | Fair Value, Nonrecurring
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets, fair value	$ 0	$ 0