Subsequent Events Supplemental Pro Forma - Combined (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Subsequent Event [Line Items]
Business Acquisition, Pro Forma Revenue	$ 888	$ 759	$ 2,503	$ 2,225
Business Acquisition, Pro Forma Net Income (Loss)	172	157	495	530
Subsequent Event [Member]
Subsequent Event [Line Items]
Business Acquisition, Pro Forma Revenue	1,059	697	2,818	1,992
Business Acquisition, Pro Forma Net Income (Loss)	$ 188	$ 141	$ 524	$ 397