Investment Securities (Securities With Unrealized Losses And Length Of Impairment Period) (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Debt Securities, Available-for-sale [Line Items]
Fair Value, Less than 12 months	$ 6,657,214	$ 8,581,829
Unrealized Loss, Less than 12 months	534,096	118,680
Fair Value, Greater than 12 months	5,823,641	465,833
Unrealized Loss, Greater than 12 months	1,010,292	14,249
Debt Securities, Available-for-sale, Unrealized Loss Position	12,480,855	9,047,662
Unrealized Loss on AFS Debt Securities	1,544,388	132,929
U.S. government and federal agency obligations
Debt Securities, Available-for-sale [Line Items]
Fair Value, Less than 12 months	695,272	296,492
Unrealized Loss, Less than 12 months	33,081	2,241
Fair Value, Greater than 12 months	283,593	0
Unrealized Loss, Greater than 12 months	15,579	0
Debt Securities, Available-for-sale, Unrealized Loss Position	978,865	296,492
Unrealized Loss on AFS Debt Securities	48,660	2,241
Government-sponsored enterprise obligations
Debt Securities, Available-for-sale [Line Items]
Fair Value, Less than 12 months	29,954	0
Unrealized Loss, Less than 12 months	5,964	0
Fair Value, Greater than 12 months	13,221	18,899
Unrealized Loss, Greater than 12 months	6,598	919
Debt Securities, Available-for-sale, Unrealized Loss Position	43,175	18,899
Unrealized Loss on AFS Debt Securities	12,562	919
State and Municipal Obligations
Debt Securities, Available-for-sale [Line Items]
Fair Value, Less than 12 months	1,101,122	876,691
Unrealized Loss, Less than 12 months	72,473	15,874
Fair Value, Greater than 12 months	673,390	32,684
Unrealized Loss, Greater than 12 months	145,337	1,049
Debt Securities, Available-for-sale, Unrealized Loss Position	1,774,512	909,375
Unrealized Loss on AFS Debt Securities	217,810	16,923
Agency mortgage-backed securities
Debt Securities, Available-for-sale [Line Items]
Fair Value, Less than 12 months	1,970,947	3,333,691
Unrealized Loss, Less than 12 months	241,074	59,044
Fair Value, Greater than 12 months	2,450,227	265,835
Unrealized Loss, Greater than 12 months	544,264	8,720
Debt Securities, Available-for-sale, Unrealized Loss Position	4,421,174	3,599,526
Unrealized Loss on AFS Debt Securities	785,338	67,764
Non-Agency Mortgage-Backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Fair Value, Less than 12 months	417,434	1,285,611
Unrealized Loss, Less than 12 months	63,282	17,222
Fair Value, Greater than 12 months	811,318	1,948
Unrealized Loss, Greater than 12 months	150,299	19
Debt Securities, Available-for-sale, Unrealized Loss Position	1,228,752	1,287,559
Unrealized Loss on AFS Debt Securities	213,581	17,241
Asset-backed securities
Debt Securities, Available-for-sale [Line Items]
Fair Value, Less than 12 months	2,145,330	2,518,935
Unrealized Loss, Less than 12 months	92,243	19,201
Fair Value, Greater than 12 months	1,381,680	87,893
Unrealized Loss, Greater than 12 months	105,368	525
Debt Securities, Available-for-sale, Unrealized Loss Position	3,527,010	2,606,828
Unrealized Loss on AFS Debt Securities	197,611	19,726
Total Mortgage And Asset-Backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Fair Value, Less than 12 months	4,533,711	7,138,237
Unrealized Loss, Less than 12 months	396,599	95,467
Fair Value, Greater than 12 months	4,643,225	355,676
Unrealized Loss, Greater than 12 months	799,931	9,264
Debt Securities, Available-for-sale, Unrealized Loss Position	9,176,936	7,493,913
Unrealized Loss on AFS Debt Securities	1,196,530	104,731
Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Fair Value, Less than 12 months	297,155	270,409
Unrealized Loss, Less than 12 months	25,979	5,098
Fair Value, Greater than 12 months	210,212	58,574
Unrealized Loss, Greater than 12 months	42,847	3,017
Debt Securities, Available-for-sale, Unrealized Loss Position	507,367	328,983
Unrealized Loss on AFS Debt Securities	$ 68,826	$ 8,115

Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for more than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

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