Investments (Contractual Maturities Debt Securities) (Details) - USD ($) $ in Millions	Mar. 31, 2023	Dec. 31, 2022
Amortized cost
Total debt securities	$ 10,961
Due in one year or less	34
Due after one year through five years	135
Due after five years through ten years	228
Due after ten years	$ 10,564
Average yield
Total debt securities	1.90%
Due in one year or less	3.36%
Due after one year through five years	3.06%
Due after five years through ten years	3.04%
Due after ten years	1.86%
Amortized cost
Available-for-sale	$ 13,075	$ 13,538
Due in one year or less	260
Due after one year through five years	1,137
Due after five years through ten years	2,624
Due after ten years	$ 9,054
Average yield
Total debt securities	2.21%
Due in one year or less	3.63%
Due after one year through five years	2.35%
Due after five years through ten years	2.20%
Due after ten years	2.16%
Amortized cost
Total HTM and AFS investment securities	$ 24,036	$ 24,664
Due in one year or less	294
Due after one year through five years	1,272
Due after five years through ten years	2,852
Due after ten years	$ 19,618
Average yield
Total debt securities	2.07%
Due in one year or less	3.60%
Due after one year through five years	2.43%
Due after five years through ten years	2.26%
Due after ten years	2.00%
Municipal securities
Amortized cost
Total debt securities	$ 392
Due in one year or less	34
Due after one year through five years	135
Due after five years through ten years	180
Due after ten years	$ 43
Average yield
Total debt securities	3.17%
Due in one year or less	3.36%
Due after one year through five years	3.06%
Due after five years through ten years	3.31%
Due after ten years	2.80%
Amortized cost
Available-for-sale	$ 1,517
Due in one year or less	119
Due after one year through five years	517
Due after five years through ten years	680
Due after ten years	$ 201
Average yield
Total debt securities	2.19%
Due in one year or less	2.49%
Due after one year through five years	2.62%
Due after five years through ten years	1.86%
Due after ten years	2.05%
U.S. Treasury securities
Amortized cost
Available-for-sale	$ 656
Due in one year or less	99
Due after one year through five years	0
Due after five years through ten years	0
Due after ten years	$ 557
Average yield
Total debt securities	2.43%
Due in one year or less	4.56%
Due after one year through five years	0.00%
Due after five years through ten years	0.00%
Due after ten years	2.05%
Agency securities
Amortized cost
Total debt securities	$ 98
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	$ 98
Average yield
Total debt securities	3.51%
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	3.51%
Amortized cost
Available-for-sale	$ 753
Due in one year or less	18
Due after one year through five years	313
Due after five years through ten years	224
Due after ten years	$ 198
Average yield
Total debt securities	2.63%
Due in one year or less	5.22%
Due after one year through five years	2.23%
Due after five years through ten years	2.54%
Due after ten years	3.12%
Agency guaranteed mortgage-backed securities
Amortized cost
Total debt securities	$ 10,471
Due in one year or less	0
Due after one year through five years	0
Due after five years through ten years	48
Due after ten years	$ 10,423
Average yield
Total debt securities	1.84%
Due in one year or less	0.00%
Due after one year through five years	0.00%
Due after five years through ten years	2.00%
Due after ten years	1.84%
Amortized cost
Available-for-sale	$ 9,423
Due in one year or less	24
Due after one year through five years	268
Due after five years through ten years	1,559
Due after ten years	$ 7,572
Average yield
Total debt securities	1.96%
Due in one year or less	4.32%
Due after one year through five years	1.55%
Due after five years through ten years	2.06%
Due after ten years	1.94%
Small Business Administration loan-backed securities
Amortized cost
Available-for-sale	$ 701
Due in one year or less	0
Due after one year through five years	39
Due after five years through ten years	151
Due after ten years	$ 511
Average yield
Total debt securities	4.80%
Due in one year or less	0.00%
Due after one year through five years	5.31%
Due after five years through ten years	4.14%
Due after ten years	4.96%
Other debt securities
Amortized cost
Available-for-sale	$ 25
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
Average yield
Total debt securities	8.27%
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	7.45%