Investment Securities (Contractual Maturity Distribution Of Debt Securities) (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2014		Dec. 31, 2013
Within one year, Amortized Cost	$ 131
After one year through five years, Amortized Cost	443
After five years through ten years, Amortized Cost	571
After ten years, Amortized Cost	8,108
Subtotal, Amortized Cost	9,253
Total investment securities available-for-sale, Amortized Cost	9,491	[1]	9,414	[1]
Within one year, Fair Value	132
After one year through five years, Fair Value	442
After five years through ten years, Fair Value	600
After ten years, Fair Value	8,056
Subtotal, Fair Value	9,230
Total investment securities available-for-sale, Fair Value	9,468	[1]	9,307	[1]
Equity and Other Non-Debt Securities
Total investment securities available-for-sale, Amortized Cost	238		266
Total investment securities available-for-sale, Fair Value	$ 238		$ 258

[1] Included auction-rate securities at amortized cost and fair value of $138 million and $137 million, respectively, as of September 30, 2014 and $169 million and $159 million, respectively, as of December 31, 2013.