Investment Securities (Summary Of Agency Securities Estimated Weighted Average Life Classifications) (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Fair Value	$ 40,904	$ 54,421
Amortized Cost	$ 44,880	$ 53,628
Weighted Average Coupon	3.94%	3.08%
Weighted Average Yield	3.37%	2.43%
Less Than or Equal to Three Years [Member]
Fair Value	$ 512	$ 1,677
Amortized Cost	$ 537	$ 1,642
Weighted Average Coupon	5.19%	3.64%
Weighted Average Yield	4.66%	3.69%
Greater Than Three Years and Less Than or Equal to Five Years [Member]
Fair Value	$ 2,643	$ 11,214
Amortized Cost	$ 2,824	$ 10,868
Weighted Average Coupon	4.57%	3.97%
Weighted Average Yield	3.79%	2.74%
Greater Than Five Years [Member]
Fair Value	$ 30,958	$ 36,936
Amortized Cost	$ 33,985	$ 36,490
Weighted Average Coupon	3.96%	2.87%
Weighted Average Yield	3.30%	2.32%
Greater Than Ten Years [Member]
Fair Value	$ 6,791	$ 4,594
Amortized Cost	$ 7,534	$ 4,628
Weighted Average Coupon	3.56%	2.48%
Weighted Average Yield	3.43%	2.09%