Credit Quality And Allowance For Credit Losses (Changes In The Allowance For Credit Losses On Lending-Related Commitments) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Financing Receivable, Allowance for Credit Losses [Line Items]
Provision for credit losses on lending-related commitments	$ 2	$ 5	$ 11	$ 9	$ 9	$ 8	$ 13	$ 16	$ 27	$ 46	$ 79
Loan Origination Commitments [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of period				36				32	36	32	26
Provision for credit losses on lending-related commitments									5	4	6
Balance at end of period	$ 41				$ 36				$ 41	$ 36	$ 32