Securities (Scheduled Contractual Maturities of AFS Debt Securities) (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Amortized Cost
Due within one year	$ 1,379,762
Due after one year through five years	785,678
Due after five years through ten years	1,483,790
Due after ten years	4,761,912
Amortized Cost	8,411,142	$ 5,470,523
Fair Value
Due within one year	1,353,523
Due after one year through five years	790,794
Due after five years through ten years	1,491,799
Due after ten years	4,763,344
Total available-for-sale debt investment securities	8,399,460	5,544,658
Available for sale debt investment securities pledged as collateral, fair value	$ 618,081	$ 588,484

Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), with single maturity date and allocated without single maturity date, maturing in sixth through tenth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), with single maturity date and allocated without single maturity date, maturing in second through fifth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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Amortized cost excluding accrued interest, before allowance for credit loss, of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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The sum of the fair values, as of the date of each statement of financial position presented, of securities that are restricted as collateral for the payment of related debt obligations, primarily secured borrowings and repurchase agreements, and that are reclassified and separately reported in the statement of financial position because the transferee has the right by contract or custom to sell or re-pledge them.

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