Fair Value (Schedule of Assets With Fair Value Changes on Nonrecurring Basis) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets, fair value	$ 17,160	$ 14,832
Fair Value, Nonrecurring
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets, fair value	16	1
Gain (losses) from fair value changes	(17)	(2)
Private equity investments, carried at cost | Fair Value, Nonrecurring
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets, fair value	1	1
Gain (losses) from fair value changes	(1)	(1)
Collateral-dependent loans | Fair Value, Nonrecurring
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets, fair value	14	0
Gain (losses) from fair value changes	(14)	0
Other real estate owned | Fair Value, Nonrecurring
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets, fair value	1	0
Gain (losses) from fair value changes	(2)	(1)
Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets, fair value	427	216
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, carried at cost | 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	16,637	14,491
Level 2 | Fair Value, Nonrecurring
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets, fair value	15	0
Level 2 | Private equity investments, carried at cost | 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	14	0
Level 2 | Other real estate owned | Fair Value, Nonrecurring
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets, fair value	1	0
Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets, fair value	96	125
Level 3 | Fair Value, Nonrecurring
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets, fair value	1	1
Level 3 | Private equity investments, carried at cost | Fair Value, Nonrecurring
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets, fair value	1	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