Investment Securities - Schedule of Investment Securities Maturity Information (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Investment securities available for sale
Non-amortizing securities maturing in one year or less, cost	$ 37	$ 0
Non-amortizing securities maturing in after one through five years, cost	2,068	2,049
Non-amortizing securities maturing in after five through 10 years, cost	483	523
Non-amortizing securities maturing in after 10 years, cost	17	17
Investment securities available for sale, cost	9,967	9,215
Non-amortizing securities maturing in one year or less, fair value	37	0
Non-amortizing securities maturing in after one through five years, fair value	1,928	2,048
Non-amortizing securities maturing in after five through 10 years, fair value	455	548
Non-amortizing securities maturing in after 10 years, fair value	14	17
Investment securities available for sale, fair value	8,995	9,203
Investment securities held to maturity
Non-amortizing securities maturing in one year or less, cost	51	2
Non-amortizing securities maturing in after one through five years, cost	1,479	0
Non-amortizing securities maturing in after five through 10 years, cost	789	0
Investment securities held to maturity, cost	10,279	3,809
Non-amortizing securities maturing in one year or less, fair value	51	2
Non-amortizing securities maturing in after one through five years, fair value	1,328	0
Non-amortizing securities maturing in after five through 10 years, fair value	663	0
Investment securities held to maturity, cost, fair value	8,795	3,759
Government agency
Investment securities available for sale
Without single maturity date, cost	164	221
Without single maturity date, fair value	162	221
Residential mortgage-backed securities
Investment securities available for sale
Without single maturity date, cost	5,424	4,757
Without single maturity date, fair value	4,795	4,729
Investment securities held to maturity
Without single maturity date, cost	4,605	2,322
Without single maturity date, fair value	3,882	2,306
Commercial mortgage-backed securities
Investment securities available for sale
Without single maturity date, cost	1,774	1,648
Without single maturity date, fair value	1,604	1,640
Investment securities held to maturity
Without single maturity date, cost	3,355	1,485
Without single maturity date, fair value	$ 2,871	$ 1,451