v3.19.3.a.u2
Debt Securities (Schedule Of Cost And Estimated Fair Value Of Securities Available For Sale And Securities Held To Maturity By Contractual Maturity) (Details) - USD ($)
$ in Millions
Dec. 31, 2019
Dec. 31, 2018
Debt Securities held to maturity, amortized cost $ 1,361 $ 1,517
Debt Securities held to maturity, estimated fair value 1,372 1,460
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, within One Year, Amortized Cost 79  
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, within One Year, Fair Value 79  
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, after One Through Five Years, Amortized Cost 1,089  
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, after One Through Five Years, Fair Value 1,110  
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, after Five Through Ten Years, Amortized Cost 415  
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, after Five Through Ten Years, Fair Value 432  
Debt Securities, Available-for-sale, Allocated and Single Maturity Date, Maturity, after 10 Years, Amortized Cost 53  
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, after 10 Years, Fair Value 55  
Debt Securities, Available-for-sale, Amortized Cost 22,332 23,258
Debt securities available for sale 22,606 22,729
Residential Agency [Member]    
Debt Securities held to maturity, amortized cost 736 883
Debt Securities held to maturity, estimated fair value 732 842
Debt Securities, Available-for-sale, Amortized Cost 15,336 17,064
Debt securities available for sale 15,516 16,624
Residential Non-Agency [Member]    
Debt Securities, Available-for-sale, Amortized Cost 1 2
Debt securities available for sale 1 2
Commercial Agency [Member]    
Debt Securities held to maturity, amortized cost 625 634
Debt Securities held to maturity, estimated fair value 640 618
Debt Securities, Available-for-sale, Amortized Cost 4,720 3,891
Debt securities available for sale 4,766 3,835
Commercial Non Agency [Member]    
Debt Securities, Available-for-sale, Amortized Cost 639 768
Debt securities available for sale $ 647 $ 760