Investment Securities (Available For Sale with Unrealized Losses, Aggregated by Category and Period of Continuous Unrealized Loss) (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Available for sale securities
Less than 12 months Fair Value	$ 215,409	$ 63,104
Less than 12 months Unrealized Losses	3,503	564
12 months or longer Fair Value	40,938	10,596
12 months or longer Unrealized Losses	1,406	83
Total Fair Value	256,347	73,700
Total Unrealized Losses	4,909	647
U.S. agency mortgage-backed securities [Member]
Available for sale securities
Less than 12 months Fair Value	186,955	61,706
Less than 12 months Unrealized Losses	3,216	551
12 months or longer Fair Value	38,007	4,774
12 months or longer Unrealized Losses	1,373	12
Total Fair Value	224,962	66,480
Total Unrealized Losses	4,589	563
U.S. Treasury securities [Member]
Available for sale securities
Less than 12 months Fair Value	16,658
Less than 12 months Unrealized Losses	125
12 months or longer Fair Value	21
12 months or longer Unrealized Losses	0
Total Fair Value	16,679
Total Unrealized Losses	125
Asset-backed securities [Member]
Available for sale securities
Less than 12 months Fair Value	6,093	1,398
Less than 12 months Unrealized Losses	58	13
12 months or longer Fair Value	2,708	5,822
12 months or longer Unrealized Losses	22	71
Total Fair Value	8,801	7,220
Total Unrealized Losses	80	$ 84
Corporate debt securities [Member]
Available for sale securities
Less than 12 months Fair Value	4,713
Less than 12 months Unrealized Losses	99
12 months or longer Fair Value	197
12 months or longer Unrealized Losses	10
Total Fair Value	4,910
Total Unrealized Losses	109
Certificates of deposit [Member]
Available for sale securities
Less than 12 months Fair Value	799
Less than 12 months Unrealized Losses	1
12 months or longer Fair Value	0
12 months or longer Unrealized Losses	0
Total Fair Value	799
Total Unrealized Losses	1
U.S. state and municipal securities [Member]
Available for sale securities
Less than 12 months Fair Value	191
Less than 12 months Unrealized Losses	4
12 months or longer Fair Value	5
12 months or longer Unrealized Losses	1
Total Fair Value	196
Total Unrealized Losses	$ 5