Derivatives (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023	Dec. 31, 2023
Derivatives, Fair Value [Line Items]
Maximum Amount of Future Payments under Credit Default Swaps	$ 13,952		$ 13,952		$ 12,468
Estimated Fair Value Assets	8,241		8,241		8,737
Estimated Fair Value Liabilities	7,347		7,347		6,298
Excess securities collateral received on derivatives	150		150		$ 163
Collateral Amount Not Provided Due to Downgrade Threshold	15		15
Derivative Instrument Detail [Abstract]
Net amounts reclassified into net derivatives gains (losses) on discontinued cash flow hedges	4	$ 26	$ (6)	$ 27
Hedging exposure to variability in future cash flows for specific length of time			5 years		5 years
Accumulated Other Comprehensive Income Loss	25		$ 25		$ 166
Cumulative foreign currency translation gain (loss) recorded in accumulated other comprehensive income (loss) for net investment in foreign operations hedges	1,100		1,100		681
Excess securities collateral provided on derivatives	80		80		98
Securities collateral received which the company is permitted to sell or repledge, amount that has been sold or repledged	0		0
Cash Flow Hedge Gain (Loss) to be Reclassified within Twelve Months			42
Over the Counter [Member]
Derivatives, Fair Value [Line Items]
Excess securities collateral received on derivatives	(499)		(499)		(298)
Excess securities collateral provided on derivatives	(1,200)		(1,200)		(1,500)
Cash collateral on derivative assets	(3,272)		(3,272)		(3,448)
Exchange-traded
Derivatives, Fair Value [Line Items]
Excess securities collateral provided on derivatives	(169)		(169)		(137)
Cash collateral on derivative assets	0		0		0
Accrued Liabilities [Member]
Derivatives, Fair Value [Line Items]
Estimated Fair Value Assets	179		179		181
Estimated Fair Value Liabilities	$ 89		$ 89		$ 9