Derivative Instruments and Hedging Activities (Fair Value Amounts of Derivative Instruments Reported on our Condensed Consolidated Balance Sheet) (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Derivatives, Fair Value [Line Items]
receivable position	$ 12	$ 33
payable position	11	17
Notional amount	40,064	44,468
Credit derivative, maximum exposure, undiscounted	24	29
Total derivatives designated as accounting hedges
Derivatives, Fair Value [Line Items]
receivable position	9	31
payable position	0	6
Notional amount	38,800	42,251
Total derivatives not designated as accounting hedges
Derivatives, Fair Value [Line Items]
receivable position	3	2
payable position	11	11
Notional amount	1,264	2,217
Interest rate contracts | Total derivatives not designated as accounting hedges
Derivatives, Fair Value [Line Items]
receivable position	2	2
payable position	0	0
Notional amount	1,207	2,158
Swaps | Total derivatives designated as accounting hedges
Derivatives, Fair Value [Line Items]
receivable position	0	0
payable position	0	0
Notional amount	32,390	35,835
Swaps | Total derivatives not designated as accounting hedges
Derivatives, Fair Value [Line Items]
receivable position	0	0
payable position	0	0
Notional amount	1,000	2,000
Purchased options | Total derivatives designated as accounting hedges
Derivatives, Fair Value [Line Items]
receivable position	9	31
payable position	0	0
Notional amount	6,250	6,250
Forwards | Total derivatives not designated as accounting hedges
Derivatives, Fair Value [Line Items]
receivable position	0	0
payable position	0	0
Notional amount	92	70
Written options | Total derivatives not designated as accounting hedges
Derivatives, Fair Value [Line Items]
receivable position	2	2
payable position	0	0
Notional amount	115	88
Foreign exchange contracts | Total derivatives not designated as accounting hedges
Derivatives, Fair Value [Line Items]
receivable position	0	0
payable position	0	1
Notional amount	57	59
Forwards | Total derivatives designated as accounting hedges
Derivatives, Fair Value [Line Items]
receivable position	0	0
payable position	0	6
Notional amount	160	166
Forwards | Total derivatives not designated as accounting hedges
Derivatives, Fair Value [Line Items]
receivable position	0	0
payable position	0	1
Notional amount	57	59
Other credit derivatives | Total derivatives not designated as accounting hedges
Derivatives, Fair Value [Line Items]
receivable position	0	0
payable position	10	10
Equity contracts | Total derivatives not designated as accounting hedges
Derivatives, Fair Value [Line Items]
receivable position	1	0
payable position	1	0
Notional amount	0	0
Written options | Total derivatives not designated as accounting hedges
Derivatives, Fair Value [Line Items]
receivable position	0	0
payable position	1	0
Notional amount	0	0
Purchased options | Total derivatives not designated as accounting hedges
Derivatives, Fair Value [Line Items]
receivable position	1	0
payable position	0	0
Notional amount	$ 0	$ 0