Equity Investments (Schedule of Equity Investments) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Schedule of Equity Method Investments [Line Items]
Equity method investments	$ 106	$ 296
ProServ Group Inc. [Member]
Schedule of Equity Method Investments [Line Items]
Equity method investments	0	168
Other Equity Investments [Member]
Schedule of Equity Method Investments [Line Items]
Equity method investments	$ 106	$ 128