Investments (Contractual Maturities Debt Securities) (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Held-to-maturity, Amortized cost
Total debt securities	$ 10,382	$ 11,126
Due in one year or less	26
Due after one year through five years	127
Due after five years through ten years	211
Due after ten years	$ 10,018
Held-to-maturity, Weighted average yield
Total debt securities	1.91%
Due in one year or less	2.70%
Due after one year through five years	3.00%
Due after five years through ten years	3.06%
Due after ten years	1.87%
Available-for-sale, Amortized cost
Total debt securities	$ 11,759	13,538
Due in one year or less	442
Due after one year through five years	782
Due after five years through ten years	2,534
Due after ten years	$ 8,001
Available-for-sale, Weighted average yield
Total debt securities	2.32%
Due in one year or less	3.24%
Due after one year through five years	2.61%
Due after five years through ten years	2.24%
Due after ten years	2.26%
Total investment securities, Amortized cost
Total HTM and AFS investment securities	$ 22,141	24,664
Due in one year or less	468
Due after one year through five years	909
Due after five years through ten years	2,745
Due after ten years	$ 18,019
Total investment securities, Weighted average yield
Total debt securities	2.13%
Due in one year or less	3.21%
Due after one year through five years	2.67%
Due after five years through ten years	2.30%
Due after ten years	2.04%
U.S. Treasury securities
Available-for-sale, Amortized cost
Total debt securities	$ 585	557
Due in one year or less	184
Due after one year through five years	0
Due after five years through ten years	0
Due after ten years	$ 401
Available-for-sale, Weighted average yield
Total debt securities	3.26%
Due in one year or less	5.24%
Due after one year through five years	0.00%
Due after five years through ten years	0.00%
Due after ten years	2.35%
Agency securities
Held-to-maturity, Amortized cost
Total debt securities	$ 93	100
Due in one year or less	0
Due after one year through five years	0
Due after five years through ten years	0
Due after ten years	$ 93
Held-to-maturity, Weighted average yield
Total debt securities	3.55%
Due in one year or less	0.00%
Due after one year through five years	0.00%
Due after five years through ten years	0.00%
Due after ten years	3.55%
Available-for-sale, Amortized cost
Total debt securities	$ 663	782
Due in one year or less	116
Due after one year through five years	154
Due after five years through ten years	207
Due after ten years	$ 186
Available-for-sale, Weighted average yield
Total debt securities	2.63%
Due in one year or less	0.93%
Due after one year through five years	3.16%
Due after five years through ten years	2.73%
Due after ten years	3.15%
Agency guaranteed mortgage-backed securities
Held-to-maturity, Amortized cost
Total debt securities	$ 9,935	10,621
Due in one year or less	0
Due after one year through five years	0
Due after five years through ten years	45
Due after ten years	$ 9,890
Held-to-maturity, Weighted average yield
Total debt securities	1.85%
Due in one year or less	0.00%
Due after one year through five years	0.00%
Due after five years through ten years	1.94%
Due after ten years	1.85%
Available-for-sale, Amortized cost
Total debt securities	$ 8,530	9,652
Due in one year or less	3
Due after one year through five years	174
Due after five years through ten years	1,459
Due after ten years	$ 6,894
Available-for-sale, Weighted average yield
Total debt securities	2.01%
Due in one year or less	1.40%
Due after one year through five years	1.63%
Due after five years through ten years	2.11%
Due after ten years	2.00%
Small Business Administration loan-backed securities
Available-for-sale, Amortized cost
Total debt securities	$ 571	740
Due in one year or less	1
Due after one year through five years	22
Due after five years through ten years	141
Due after ten years	$ 407
Available-for-sale, Weighted average yield
Total debt securities	5.54%
Due in one year or less	5.33%
Due after one year through five years	6.33%
Due after five years through ten years	4.40%
Due after ten years	5.89%
Municipal securities
Held-to-maturity, Amortized cost
Total debt securities	$ 354	405
Due in one year or less	26
Due after one year through five years	127
Due after five years through ten years	166
Due after ten years	$ 35
Held-to-maturity, Weighted average yield
Total debt securities	3.15%
Due in one year or less	2.70%
Due after one year through five years	3.00%
Due after five years through ten years	3.36%
Due after ten years	3.08%
Available-for-sale, Amortized cost
Total debt securities	$ 1,385	1,732
Due in one year or less	138
Due after one year through five years	432
Due after five years through ten years	717
Due after ten years	$ 98
Available-for-sale, Weighted average yield
Total debt securities	2.18%
Due in one year or less	2.54%
Due after one year through five years	2.63%
Due after five years through ten years	1.84%
Due after ten years	2.22%
Other debt securities
Available-for-sale, Amortized cost
Total debt securities	$ 25	$ 75
Due in one year or less	0
Due after one year through five years	0
Due after five years through ten years	10
Due after ten years	$ 15
Available-for-sale, Weighted average yield
Total debt securities	8.77%
Due in one year or less	0.00%
Due after one year through five years	0.00%
Due after five years through ten years	9.50%
Due after ten years	8.28%