Equity Method Investments (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Schedule of Equity Method Investments [Line Items]
Income (Loss) from Equity Method Investments, Net of Dividends or Distributions	$ (33)		$ 17		$ (7)
Distributions from Equity Method Investments	156		0		0
Equity Method Investments	325		437		367
Equity Method Investment, Financial Statement, Reported Amounts [Abstract]
Retained earnings related to undistributed earnings of equity method investees	100
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	8
Balance Sheet Information
Current Assets	412		463
Noncurrent Assets	1,169		983
Current Liabilities	374		373
Noncurrent Liabilities	33		29
Statements of Operations Information
Operating Revenues	1,142		1,256		1,173
Operating Expenses	405		388		361
Operating Income	737		868		812
Other (Income), Net	(9)		(14)		(5)
Income Before Income Taxes	746		882		817
Income Tax Provision	172		212		200
Net Income	574		670		617
AMPCO [Member]
Schedule of Equity Method Investments [Line Items]
Ownership interest in equity method investments (in hundredths)	45.00%
Equity Method Investments	141		139
Alba Plant [Member]
Schedule of Equity Method Investments [Line Items]
Ownership interest in equity method investments (in hundredths)	28.00%
Equity Method Investments	82		95
CONE Gathering LLC [Member]
Schedule of Equity Method Investments [Line Items]
Ownership interest in equity method investments (in hundredths)	50.00%
Distribution from Offering Proceeds	204
Income (Loss) from Equity Method Investments, Net of Dividends or Distributions	48
Distributions from Equity Method Investments	156
Equity Method Investments	82	[1]	184	[1]
CONE Midstream [Member]
Schedule of Equity Method Investments [Line Items]
Ownership interest in equity method investments (in hundredths)	32.00%
Other Investees [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investments	$ 20		$ 19

[1] CONE Investments includes our investments in CONE Midstream and CONE Gathering.