Investment Securities (Securities With Unrealized Losses And Length Of Impairment Period) (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Debt Securities, Available-for-sale [Line Items]
Fair Value, Less than 12 months	$ 658,346	$ 99,075
Unrealized Loss, Less than 12 months	2,765	1,784
Fair Value, Greater than 12 months	7,324,522	9,494,875
Unrealized Loss, Greater than 12 months	1,073,277	1,218,700
Debt Securities, Available-for-sale, Unrealized Loss Position	7,982,868	9,593,950
Unrealized Loss on AFS Debt Securities	1,076,042	1,220,484
U.S. government and federal agency obligations
Debt Securities, Available-for-sale [Line Items]
Fair Value, Less than 12 months	647,825	51,585
Unrealized Loss, Less than 12 months	2,025	809
Fair Value, Greater than 12 months	509,058	714,400
Unrealized Loss, Greater than 12 months	23,119	24,025
Debt Securities, Available-for-sale, Unrealized Loss Position	1,156,883	765,985
Unrealized Loss on AFS Debt Securities	25,144	24,834
Government-sponsored enterprise obligations
Debt Securities, Available-for-sale [Line Items]
Fair Value, Less than 12 months	0	0
Unrealized Loss, Less than 12 months	0	0
Fair Value, Greater than 12 months	43,139	43,962
Unrealized Loss, Greater than 12 months	12,490	11,696
Debt Securities, Available-for-sale, Unrealized Loss Position	43,139	43,962
Unrealized Loss on AFS Debt Securities	12,490	11,696
State and municipal obligations [Member]
Debt Securities, Available-for-sale [Line Items]
Fair Value, Less than 12 months	9,885	24,022
Unrealized Loss, Less than 12 months	735	760
Fair Value, Greater than 12 months	763,769	1,167,607
Unrealized Loss, Greater than 12 months	93,213	148,478
Debt Securities, Available-for-sale, Unrealized Loss Position	773,654	1,191,629
Unrealized Loss on AFS Debt Securities	93,948	149,238
Agency mortgage-backed securities
Debt Securities, Available-for-sale [Line Items]
Fair Value, Less than 12 months	636	4,382
Unrealized Loss, Less than 12 months	5	59
Fair Value, Greater than 12 months	3,604,732	3,875,432
Unrealized Loss, Greater than 12 months	781,585	720,649
Debt Securities, Available-for-sale, Unrealized Loss Position	3,605,368	3,879,814
Unrealized Loss on AFS Debt Securities	781,590	720,708
Non-Agency Mortgage-Backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Fair Value, Less than 12 months	0	0
Unrealized Loss, Less than 12 months	0	0
Fair Value, Greater than 12 months	641,907	1,152,045
Unrealized Loss, Greater than 12 months	82,800	173,526
Debt Securities, Available-for-sale, Unrealized Loss Position	641,907	1,152,045
Unrealized Loss on AFS Debt Securities	82,800	173,526
Asset-backed securities
Debt Securities, Available-for-sale [Line Items]
Fair Value, Less than 12 months	0	19,086
Unrealized Loss, Less than 12 months	0	156
Fair Value, Greater than 12 months	1,544,995	2,081,293
Unrealized Loss, Greater than 12 months	62,995	93,076
Debt Securities, Available-for-sale, Unrealized Loss Position	1,544,995	2,100,379
Unrealized Loss on AFS Debt Securities	62,995	93,232
Total Mortgage And Asset-Backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Fair Value, Less than 12 months	636	23,468
Unrealized Loss, Less than 12 months	5	215
Fair Value, Greater than 12 months	5,791,634	7,108,770
Unrealized Loss, Greater than 12 months	927,380	987,251
Debt Securities, Available-for-sale, Unrealized Loss Position	5,792,270	7,132,238
Unrealized Loss on AFS Debt Securities	927,385	987,466
Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Fair Value, Less than 12 months	0	0
Unrealized Loss, Less than 12 months	0	0
Fair Value, Greater than 12 months	216,922	460,136
Unrealized Loss, Greater than 12 months	17,075	47,250
Debt Securities, Available-for-sale, Unrealized Loss Position	216,922	460,136
Unrealized Loss on AFS Debt Securities	$ 17,075	$ 47,250