Goodwill And Intangible Assets, Net (Information Regarding Intangible Assets) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Jun. 30, 2012	Mar. 31, 2012
Intangible assets
Gross Carrying Amount	$ 2,588	$ 2,615
Accumulated Amortization	(910)	(865)
Net Carrying Amount	1,678	1,750
Customer Lists [Member]
Intangible assets
Weighted Average Remaining Amortization Period (years)	P7Y
Gross Carrying Amount	1,082	1,081
Accumulated Amortization	(579)	(554)
Net Carrying Amount	503	527
Service Agreements [Member]
Intangible assets
Weighted Average Remaining Amortization Period (years)	P18Y
Gross Carrying Amount	994	1,022
Accumulated Amortization	(65)	(52)
Net Carrying Amount	929	970
Trademarks And Trade Names [Member]
Intangible assets
Weighted Average Remaining Amortization Period (years)	P18Y
Gross Carrying Amount	191	192
Accumulated Amortization	(40)	(38)
Net Carrying Amount	151	154
Technology [Member]
Intangible assets
Weighted Average Remaining Amortization Period (years)	P3Y
Gross Carrying Amount	243	244
Accumulated Amortization	(193)	(190)
Net Carrying Amount	50	54
Other [Member]
Intangible assets
Weighted Average Remaining Amortization Period (years)	P8Y
Gross Carrying Amount	78	76
Accumulated Amortization	(33)	(31)
Net Carrying Amount	$ 45	$ 45