Investment Securities - Amortized Cost, Fair Value, by Contract Maturity (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Available-for-sale securities, Amortized Cost:
Due in one year or less	$ 29,394
Due after one year through five years	63,634
Due after five years through 10 years	30,505
Due after 10 years	92,684
Amortized cost	216,217
Available-for-sale securities, Fair value
Due in one year or less	29,009
Due after one year through five years	61,070
Due after five years through 10 years	29,368
Due after 10 years	86,410
Fair value	$ 205,857	$ 308,525
Available-for-sale securities, Average yield
Due in one year or less	2.34%
Due after one year through five years	3.05%
Due after five years through 10 years	3.94%
Due after 10 years	4.01%
Average yield	3.49%
Held-to-maturity securities, Amortized cost
Due in one year or less	$ 34,255
Due after one year through five years	108,179
Due after five years through 10 years	101,470
Due after 10 years	181,468
Amortized cost	425,372
Held-to-maturity securities, Fair value
Due in one year or less	33,529
Due after one year through five years	101,058
Due after five years through 10 years	89,026
Due after 10 years	165,035
Fair value	$ 388,648	362,628
Held-to-maturity securities, Average yield
Due in one year or less	0.58%
Due after one year through five years	0.74%
Due after five years through 10 years	2.18%
Due after 10 years	3.50%
Average yield	2.25%
Supplemental information
Agency residential MBS estimated duration	8 years
Agency residential collateralized mortgage obligations estimated duration	6 years
Nonagency residential collateralized mortgage obligations estimated duration	6 years
Minimum
Supplemental information
Due period of mortgage-backed securities and collateralized mortgage obligations	10 years
Total mortgage-backed securities
Available-for-sale securities, Amortized Cost:
Due in one year or less	$ 14
Due after one year through five years	3,634
Due after five years through 10 years	4,534
Due after 10 years	75,877
Amortized cost	84,059
Available-for-sale securities, Fair value
Due in one year or less	14
Due after one year through five years	3,459
Due after five years through 10 years	4,573
Due after 10 years	70,035
Fair value	$ 78,081	83,562
Available-for-sale securities, Average yield
Due in one year or less	2.21%
Due after one year through five years	3.58%
Due after five years through 10 years	5.25%
Due after 10 years	3.62%
Average yield	3.71%
Held-to-maturity securities, Amortized cost
Due in one year or less	$ 98
Due after one year through five years	1,718
Due after five years through 10 years	12,350
Due after 10 years	120,206
Amortized cost	134,372
Held-to-maturity securities, Fair value
Due in one year or less	96
Due after one year through five years	1,584
Due after five years through 10 years	10,909
Due after 10 years	106,128
Fair value	$ 118,717	114,001
Held-to-maturity securities, Average yield
Due in one year or less	5.54%
Due after one year through five years	2.23%
Due after five years through 10 years	2.56%
Due after 10 years	2.93%
Average yield	2.89%
U.S. Treasury and government agencies
Available-for-sale securities, Amortized Cost:
Due in one year or less	$ 16,335
Due after one year through five years	54,936
Due after five years through 10 years	17,749
Due after 10 years	6,197
Amortized cost	95,217
Available-for-sale securities, Fair value
Due in one year or less	16,011
Due after one year through five years	52,703
Due after five years through 10 years	17,167
Due after 10 years	6,179
Fair value	$ 92,060	177,463
Available-for-sale securities, Average yield
Due in one year or less	1.27%
Due after one year through five years	3.00%
Due after five years through 10 years	3.99%
Due after 10 years	6.01%
Average yield	3.08%
Held-to-maturity securities, Amortized cost
Due in one year or less	$ 34,157
Due after one year through five years	106,325
Due after five years through 10 years	66,981
Due after 10 years	0
Amortized cost	207,463
Held-to-maturity securities, Fair value
Due in one year or less	33,433
Due after one year through five years	99,345
Due after five years through 10 years	56,322
Due after 10 years	0
Fair value	$ 189,100	183,270
Held-to-maturity securities, Average yield
Due in one year or less	0.57%
Due after one year through five years	0.71%
Due after five years through 10 years	1.27%
Due after 10 years	0.00%
Average yield	0.87%
Obligations of U.S. states and municipalities
Available-for-sale securities, Amortized Cost:
Due in one year or less	$ 18
Due after one year through five years	47
Due after five years through 10 years	215
Due after 10 years	6,823
Amortized cost	7,103
Available-for-sale securities, Fair value
Due in one year or less	18
Due after one year through five years	46
Due after five years through 10 years	216
Due after 10 years	6,506
Fair value	$ 6,786	15,860
Available-for-sale securities, Average yield
Due in one year or less	5.03%
Due after one year through five years	3.96%
Due after five years through 10 years	5.24%
Due after 10 years	5.85%
Average yield	5.81%
Held-to-maturity securities, Amortized cost
Due in one year or less	$ 0
Due after one year through five years	106
Due after five years through 10 years	2,741
Due after 10 years	16,951
Amortized cost	19,798
Held-to-maturity securities, Fair value
Due in one year or less	0
Due after one year through five years	100
Due after five years through 10 years	2,710
Due after 10 years	15,910
Fair value	$ 18,720	14,394
Held-to-maturity securities, Average yield
Due in one year or less	0.00%
Due after one year through five years	3.39%
Due after five years through 10 years	4.03%
Due after 10 years	4.24%
Average yield	4.21%
Non-U.S. government debt securities
Available-for-sale securities, Amortized Cost:
Due in one year or less	$ 12,803
Due after one year through five years	3,228
Due after five years through 10 years	4,329
Due after 10 years	0
Amortized cost	20,360
Available-for-sale securities, Fair value
Due in one year or less	12,795
Due after one year through five years	3,107
Due after five years through 10 years	3,794
Due after 10 years	0
Fair value	$ 19,696	16,209
Available-for-sale securities, Average yield
Due in one year or less	3.54%
Due after one year through five years	2.59%
Due after five years through 10 years	1.37%
Due after 10 years	0.00%
Average yield	2.93%
Corporate debt securities
Available-for-sale securities, Amortized Cost:
Due in one year or less	$ 125
Due after one year through five years	272
Due after five years through 10 years	13
Due after 10 years	0
Amortized cost	410
Available-for-sale securities, Fair value
Due in one year or less	76
Due after one year through five years	268
Due after five years through 10 years	13
Due after 10 years	0
Fair value	$ 357	$ 321
Available-for-sale securities, Average yield
Due in one year or less	16.22%
Due after one year through five years	12.07%
Due after five years through 10 years	5.78%
Due after 10 years	0.00%
Average yield	13.14%
Asset-backed securities
Available-for-sale securities, Amortized Cost:
Due in one year or less	$ 99
Due after one year through five years	1,517
Due after five years through 10 years	3,665
Due after 10 years	3,787
Amortized cost	9,068
Available-for-sale securities, Fair value
Due in one year or less	95
Due after one year through five years	1,487
Due after five years through 10 years	3,605
Due after 10 years	3,690
Fair value	$ 8,877
Available-for-sale securities, Average yield
Due in one year or less	5.11%
Due after one year through five years	3.11%
Due after five years through 10 years	4.98%
Due after 10 years	5.19%
Average yield	4.76%
Held-to-maturity securities, Amortized cost
Due in one year or less	$ 0
Due after one year through five years	30
Due after five years through 10 years	19,398
Due after 10 years	44,311
Amortized cost	63,739
Held-to-maturity securities, Fair value
Due in one year or less	0
Due after one year through five years	29
Due after five years through 10 years	19,085
Due after 10 years	42,997
Fair value	$ 62,111
Held-to-maturity securities, Average yield
Due in one year or less	0.00%
Due after one year through five years	5.69%
Due after five years through 10 years	4.80%
Due after 10 years	4.74%
Average yield	4.76%