Debt and Banking Arrangements (Details Textual) (USD $) In Millions, unless otherwise specified	6 Months Ended
	Jun. 30, 2011	Jun. 15, 2011
Debt and Banking Arrangements (Textuals) [Abstract]
Percentage of Debt Instrument	5.50%
Loans outstanding	$ 350
$ 900 million unsecured credit facility terminated June 2011
Debt and Banking Arrangements (Textuals) [Abstract]
Amount of unsecured credit facility	900
Loans outstanding	0
$ 1.75 WPZ billion unsecured credit facility terminated June 2011
Debt and Banking Arrangements (Textuals) [Abstract]
Amount of unsecured credit facility	1,750
Refinancing of Long-Term Lines of Credit	300
Maximum | $ 900 million unsecured credit facility effective June 2011
Debt and Banking Arrangements (Textuals) [Abstract]
Ratio of debt to EBITDA	4.5
Total aggregate purchase price of acquisitions that changes debt to EBITDA Ratio	50
Ratio of Debt to EBITDA After Acquisition	5
$ 900 million unsecured credit facility effective June 2011
Debt and Banking Arrangements (Textuals) [Abstract]
Amount of unsecured credit facility	900
Additional amount by which credit facility can be increased	250
Commitment fee	0.25%
$ 900 million unsecured credit facility effective June 2011 | Letter of Credit Capacity
Debt and Banking Arrangements (Textuals) [Abstract]
Amount of unsecured credit facility	700
Maximum | $ 2 billion WPZ unsecured credit facility
Debt and Banking Arrangements (Textuals) [Abstract]
Ratio of debt to EBITDA	5
Total aggregate purchase price of acquisitions that changes debt to EBITDA Ratio	50
Ratio of Debt to EBITDA After Acquisition	5.5
Ratio Of Debt To Capitalization For Transco And Northwest Pipeline	65.00%
$ 2 billion WPZ unsecured credit facility
Debt and Banking Arrangements (Textuals) [Abstract]
Amount of unsecured credit facility	2,000
Additional amount by which credit facility can be increased	400
Maximum amount each of Transco and Northwest pipeline can borrow	400
Commitment fee	0.25%
Net Payment of loans Outstanding	100
Loans outstanding	350
$ 2 billion WPZ unsecured credit facility | Letter of Credit Capacity
Debt and Banking Arrangements (Textuals) [Abstract]
Amount of unsecured credit facility	1,300
Maximum | $ 1.5 billion WPX unsecured credit facility
Debt and Banking Arrangements (Textuals) [Abstract]
Present Value To Debt	1.5
Ratio of debt to capitalization	60.00%
$ 1.5 billion WPX unsecured credit facility
Debt and Banking Arrangements (Textuals) [Abstract]
Amount of unsecured credit facility	1,500
Additional amount by which credit facility can be increased	300
Swing line loan capacity	125
7.5 percent senior unsecured notes matured
Debt and Banking Arrangements (Textuals) [Abstract]
Debt Retirement	$ 150
Percentage of Debt Instrument		7.50%