Investments (Contractual Maturities Debt Securities) (Details) - USD ($) $ in Millions	Jun. 30, 2022	Dec. 31, 2021
Amortized cost
Available-for-sale	$ 28,012	$ 24,202
Due in one year or less	139
Due after one year through five years	1,449
Due after five years through ten years	3,015
Due after ten years	$ 23,409
Average yield
Total debt securities	1.84%
Due in one year or less	1.79%
Due after one year through five years	2.11%
Due after five years through ten years	2.07%
Due after ten years	1.80%
Amortized cost
Total HTM and AFS investment securities	$ 28,626	$ 24,643
Due in one year or less	366
Due after one year through five years	1,586
Due after five years through ten years	3,205
Due after ten years	$ 23,469
Average yield
Total debt securities	1.86%
Due in one year or less	2.25%
Due after one year through five years	2.20%
Due after five years through ten years	2.13%
Due after ten years	1.80%
Municipal securities
Amortized cost
Total debt securities	$ 614
Due in one year or less	227
Due after one year through five years	137
Due after five years through ten years	190
Due after ten years	$ 60
Average yield
Total debt securities	2.84%
Due in one year or less	2.53%
Due after one year through five years	3.19%
Due after five years through ten years	3.03%
Due after ten years	2.59%
Amortized cost
Available-for-sale	$ 1,835
Due in one year or less	108
Due after one year through five years	670
Due after five years through ten years	694
Due after ten years	$ 363
Average yield
Total debt securities	2.40%
Due in one year or less	2.07%
Due after one year through five years	2.61%
Due after five years through ten years	2.18%
Due after ten years	2.55%
U.S. Treasury securities
Amortized cost
Available-for-sale	$ 557
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	$ 557
Average yield
Total debt securities	2.05%
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	2.05%
Agency securities
Amortized cost
Available-for-sale	$ 899
Due in one year or less	31
Due after one year through five years	340
Due after five years through ten years	285
Due after ten years	$ 243
Average yield
Total debt securities	2.33%
Due in one year or less	0.84%
Due after one year through five years	1.92%
Due after five years through ten years	2.39%
Due after ten years	3.03%
Agency guaranteed mortgage-backed securities
Amortized cost
Available-for-sale	$ 23,768
Due in one year or less	0
Due after one year through five years	391
Due after five years through ten years	1,810
Due after ten years	$ 21,567
Average yield
Total debt securities	1.79%
Due in one year or less	0.00%
Due after one year through five years	1.50%
Due after five years through ten years	1.93%
Due after ten years	1.78%
Small Business Administration loan-backed securities
Amortized cost
Available-for-sale	$ 878
Due in one year or less	0
Due after one year through five years	48
Due after five years through ten years	166
Due after ten years	$ 664
Average yield
Total debt securities	1.50%
Due in one year or less	0.00%
Due after one year through five years	1.51%
Due after five years through ten years	2.41%
Due after ten years	1.27%
Other debt securities
Amortized cost
Available-for-sale	$ 75
Due in one year or less	0
Due after one year through five years	0
Due after five years through ten years	60
Due after ten years	$ 15
Average yield
Total debt securities	2.82%
Due in one year or less	0.00%
Due after one year through five years	0.00%
Due after five years through ten years	2.61%
Due after ten years	3.67%