Fair Value Measurements (Fair Value, Assets And Liabilities Measured On Recurring Basis) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2011		Dec. 31, 2010
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	$ 43	[1]	$ 26	[1]
Derivative liabilities	26	[1]	33	[1]
Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	43	[1]	26	[1]
Derivative liabilities	26	[1]	33	[1]
Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of investments measured on recurring basis	91	[2]	86	[2]
Equity Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of investments measured on recurring basis	91	[2]	86	[2]
Mutual Funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of investments measured on recurring basis	380	[2]	450	[2]
Mutual Funds [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of investments measured on recurring basis	380	[2]	450	[2]
U.S. Government Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of investments measured on recurring basis	211	[3]	719	[3]
U.S. Government Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of investments measured on recurring basis	211	[3]	719	[3]
Other Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of investments measured on recurring basis	102	[3]	104	[3]
Other Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of investments measured on recurring basis	$ 102	[3]	$ 104	[3]

[1] Derivative assets and liabilities relate to foreign currency exchange and interest rate swap contracts and are valued based on observable market prices (e.g., interest rates and yield curves observable at commonly quoted intervals), but are not exchanged in an active market.

[2] Equity securities and interests in mutual funds are valued using quoted market prices.

[3] U.S. Government securities and other securities, which consist primarily of corporate debt securities, U.S. Government-sponsored enterprise securities, and mortgage-backed securities, 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).