Fair Value Measurements Aggregate Fair Value Of Derivative Financial Instruments And Debt (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2012
Estimate of Fair Value, Fair Value Disclosure [Member]
Foreign exchange contracts, Assets	$ 116
Total assets	116
Debt	18,493
Foreign exchange contracts, Liabilities	38
Total liabilities	18,531
Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member]
Foreign exchange contracts, Assets	0
Total assets	0
Debt	18,040
Total liabilities	18,040
Significant Other Observable Inputs (Level 2) [Member]
Foreign exchange contracts, Assets	116
Total assets	116
Debt	453
Foreign exchange contracts, Liabilities	38
Total liabilities	491
Significant Unobservable Inputs (Level 3) [Member]
Foreign exchange contracts, Assets	0
Total assets	0
Debt	0
Total liabilities	$ 0