Fair Value Measurements (Assets and Liabilities Measured and Recorded at Fair Value on Balance Sheet on a Recurring Basis and Level within Fair Value Hierarchy) (Details) (USD $) In Millions	Jun. 30, 2011		Dec. 31, 2010
Derivative assets	$ 39	[1]	$ 26	[1]
Derivative liabilities	28	[1]	33	[1]
Equity Securities [Member]
Fair value of investments measured on recurring basis	90	[1]	86	[1]
Equity Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Fair value of investments measured on recurring basis	90	[1]	86	[1]
Mutual Funds [Member]
Fair value of investments measured on recurring basis	346	[1]	450	[1]
Mutual Funds [Member] | Fair Value, Inputs, Level 1 [Member]
Fair value of investments measured on recurring basis	346	[1]	450	[1]
U.S. Government Securities [Member]
Fair value of investments measured on recurring basis	510	[1]	719	[1]
U.S. Government Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Fair value of investments measured on recurring basis	510	[1]	719	[1]
Other Securities [Member]
Fair value of investments measured on recurring basis	103	[1]	104	[1]
Other Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Fair value of investments measured on recurring basis	103	[1]	104	[1]
Fair Value, Inputs, Level 2 [Member]
Derivative assets	39	[1]	26	[1]
Derivative liabilities	$ 28	[1]	$ 33	[1]

[1] (1) We considered the following fair value hierarchy to prioritize the inputs we used in the valuation techniques to determine the fair values of the assets and liabilities included in the preceding tables: • Level 1 - Observable inputs - quoted prices in active markets for identical assets and liabilities. Level 1 assets in the preceding tables include equity securities and interests in mutual funds which are valued using quoted market prices. • Level 2 - Observable inputs other than the quoted prices in active markets for identical assets and liabilities - includes quoted prices for similar instruments, quoted prices for identical or similar instruments in inactive markets, and amounts derived from valuation models where all significant inputs are observable in active markets. Level 2 assets in the preceding tables are valued based on inputs other than quoted prices that are observable for the asset (e.g., interest rates and yield curves observable at commonly quoted intervals). The Level 2 derivative assets and liabilities relate to foreign currency exchange and interest rate swap contracts and are valued based on observable market prices, but are not exchanged in an active market.