Equity Method Investments (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011		Dec. 31, 2010		Dec. 31, 2009
Schedule of Equity Method Investments [Line Items]
Ownership interest in equity method investments (in hundredths)	50.00%
Total Equity Method Investments	$ 329	[1]	$ 285	[1]	$ 303
Equity Method Investment, Financial Statement, Reported Amounts [Abstract]
Retained earnings related to undistributed earnings of equity method investees	106
AMPCO Equity Method Investment, Difference Between Carrying Amount and Underlying Equity [Abstract]
Difference between the carrying value of an equity method investment and the underlying net assets of the investee	14
Difference between the investment's carrying value and net assets of the investee related to capitalized interest which is being amortized into earnings	10
Difference between the investment's carrying value and the net assets of the investee related to note receivable from the local government	4
Balance Sheet Information
Current Assets	374		307
Noncurrent Assets	827		735
Current Liabilities	360		265
Noncurrent Liabilities	16		16
Statements of Operations Information
Operating Revenues	1,139		809		632
Operating Expenses	335		296		264
Operating Income	804		513		368
Other (Income), Net	(12)		(12)		(13)
Income Before Income Taxes	816		525		381
Income Tax Provision	201		133		95
Net Income	615		392		286
AMPCO [Member]
Schedule of Equity Method Investments [Line Items]
Ownership interest in equity method investments (in hundredths)	45.00%
Total Equity Method Investments	147		166
Alba Plant [Member]
Schedule of Equity Method Investments [Line Items]
Ownership interest in equity method investments (in hundredths)	28.00%
Total Equity Method Investments	96		107
CONE Gathering LLC [Member]
Schedule of Equity Method Investments [Line Items]
Ownership interest in equity method investments (in hundredths)	50.00%
Total Equity Method Investments	72		0
Other Investees [Member]
Schedule of Equity Method Investments [Line Items]
Total Equity Method Investments	$ 14		$ 12

[1] The increase in equity method investments from December 31, 2010 is due primarily to our acquisition of a 50% interest in CONE. See Note 3. Acquisitions and Divestitures.