Available-For-Sale And Held-To-Maturity Securities (Schedule Of Amortized Cost Of Held-To-Maturity Securities By Credit Quality Indicator) (Details) - USD ($) $ in Thousands		Jun. 30, 2022	Dec. 31, 2021
Schedule Of Held To Maturity Securities [Line Items]
Held-to-maturity securities, at amortized cost	[1]	$ 5,883,448	$ 5,348,558
Asset-Backed Securities [Member]
Schedule Of Held To Maturity Securities [Line Items]
Held-to-maturity securities, at amortized cost		5,883,448
Asset-Backed Securities [Member] | AAA [Member]
Schedule Of Held To Maturity Securities [Line Items]
Held-to-maturity securities, at amortized cost		1,174,723
Asset-Backed Securities [Member] | AA [Member]
Schedule Of Held To Maturity Securities [Line Items]
Held-to-maturity securities, at amortized cost		4,701,488
Asset-Backed Securities [Member] | A [Member]
Schedule Of Held To Maturity Securities [Line Items]
Held-to-maturity securities, at amortized cost		5,000
Asset-Backed Securities [Member] | C [Member]
Schedule Of Held To Maturity Securities [Line Items]
Held-to-maturity securities, at amortized cost		$ 2,237

[1] Held-to-maturity securities are carried in the consolidated statements of financial condition at amortized cost, and the changes in the value of these securities, other than impairment charges, are not reported on the consolidated financial statements.