Investment Securities (Securities With Unrealized Losses And Length Of Impairment Period) (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Investment [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	$ 4,402,724	$ 8,581,829
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	250,660	118,680
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	7,625,021	465,833
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	1,249,972	14,249
Debt Securities, Available-for-sale, Unrealized Loss Position	12,027,745	9,047,662
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	1,500,632	132,929
US Treasury and Government [Member]
Investment [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	605,840	296,492
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	17,490	2,241
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	380,573	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	25,940	0
Debt Securities, Available-for-sale, Unrealized Loss Position	986,413	296,492
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	43,430	2,241
US Government-sponsored Enterprise Debt Securities [Member]
Investment [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	25,068	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	4,650	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	18,040	18,899
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	7,971	919
Debt Securities, Available-for-sale, Unrealized Loss Position	43,108	18,899
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	12,621	919
State and municipal obligations [Member]
Investment [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	814,799	876,691
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	26,708	15,874
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	875,329	32,684
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	171,385	1,049
Debt Securities, Available-for-sale, Unrealized Loss Position	1,690,128	909,375
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	198,093	16,923
Agency mortgage-backed securities [Member]
Investment [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	1,323,938	3,333,691
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	125,330	59,044
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	2,966,851	265,835
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	654,327	8,720
Debt Securities, Available-for-sale, Unrealized Loss Position	4,290,789	3,599,526
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	779,657	67,764
Non-agency mortgage-backed securities [Member]
Investment [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	135,984	1,285,611
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	16,736	17,222
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	1,069,222	1,948
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	195,218	19
Debt Securities, Available-for-sale, Unrealized Loss Position	1,205,206	1,287,559
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	211,954	17,241
Asset-backed Securities [Member]
Investment [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	1,331,055	2,518,935
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	50,056	19,201
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	2,006,188	87,893
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	140,424	525
Debt Securities, Available-for-sale, Unrealized Loss Position	3,337,243	2,606,828
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	190,480	19,726
Total mortgage and asset-backed securities [Member]
Investment [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	2,790,977	7,138,237
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	192,122	95,467
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	6,042,261	355,676
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	989,969	9,264
Debt Securities, Available-for-sale, Unrealized Loss Position	8,833,238	7,493,913
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	1,182,091	104,731
Other debt securities [Member]
Investment [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	166,040	270,409
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	9,690	5,098
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	308,818	58,574
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	54,707	3,017
Debt Securities, Available-for-sale, Unrealized Loss Position	474,858	328,983
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	$ 64,397	$ 8,115