Federal Funds Sold and Securities Borrowed or Purchased Under Agreements to Resell Netting of financial instruments - repurchase agreements (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013
Assets Sold under Agreements to Repurchase [Line Items]
Carrying Value of Securities Purchased under Agreements to Resell and Deposits Paid for Securities Borrowed	$ 1,122		$ 908
Securities Purchased under Agreements to Resell, Amount Offset Against Collateral	0		0
Federal Funds Sold and Securities Borrowed or Purchased under Agreements to Resell, Fair Value Disclosure	1,122	[1],[2]	908	[1],[2]
Held Financial Instruments, Not Separately Reported, Securities for Reverse Repurchase Agreements	1,112		899
Securities Borrowed or Purchased Under Agreements to Resell, Amount Not Offset Against Collateral	10		9
Securities Sold under Agreements to Repurchase, Gross	2,276		1,759
Securities Sold Under Agreements to Repurchase, Amount Offset Against Collateral	0		0
Securities Sold under Agreements to Repurchase	2,276	[2]	1,759	[2]
Pledged Financial Instruments, Not Separately Reported, Securities for Repurchase Agreements	2,276		1,759
Securities Sold Under Agreements to Repurchase, Amount Not Offset Against Collateral	$ 0		$ 0

[1] Excludes $38 million and $75 million of Fed funds sold which are not subject to a master netting agreement at December 31, 2014 and 2013, respectively.

[2] None of the Company's repurchase or resell transactions met the right of setoff criteria for net balance sheet presentation at December 31, 2014 and 2013.