Settlement Assets and Obligations (Details Numeric) (USD $) In Billions, unless otherwise specified	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012
Settlement Assets And Obligations (Numeric) [Abstract]
Proceeds from sale and maturity of available-for-sale securities	$ 9.3	$ 7.3
Maximum [Member]
Settlement Assets And Obligations (Numeric) [Abstract]
Variable rate demand notes, maximum maturity year	2051
Variable rate demand notes, period of time held	30 days