Other Assets (Proportional Amortization Investment) (Details) - USD ($)	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Other Assets [Abstract]
Tax credits and other tax benefits from proportional amortization investments	$ 39,000,000	$ 47,000,000
Investment amortization expense recognized as a component of income tax expense	32,000,000	38,000,000
Net Benefit from Proportional Amortization Investments	7,000,000	9,000,000
Investment program, proportional amortization method, elected, impairment loss	0	$ 0
Proportional amortization investments	1,877,000,000		$ 1,866,000,000
Unfunded commitments for proportional amortization investments	$ 917,000,000		$ 973,000,000
Unfunded commitments, period to be paid	5 years