Debt, Financing Arrangements and Leases (Details Textual) (USD $)	12 Months Ended						12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Aug. 31, 2011 $375 Million, 5.4% Senior Notes due 2041 [Member]	Jul. 31, 2012 $400 Million, 4.45% Senior Notes due 2042 [Member]	Jul. 31, 2012 $325 Million, 8.875% Senior Notes due July 15, 2012 [Member]	Dec. 31, 2012 Williams Partners L.P. [Member]	Dec. 31, 2012 $2 billion unsecured credit facility superceeded September 2012 [Member] Williams Partners L.P. [Member]	Dec. 31, 2012 $2.4 billion unsecured credit facility effective September 2012	Dec. 31, 2012 $2.4 billion unsecured credit facility effective September 2012 Williams Partners L.P. [Member]	Dec. 31, 2012 $2.4 billion unsecured credit facility effective September 2012 Williams Partners L.P. [Member] Letter of Credit [Member]
Debt,Financing Arrangements, and Leases [Abstract]
PledgedAssetsNotSeparatelyReportedOtherFinancialInstruments	$ 0
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	400,000,000							2,000,000,000		2,400,000,000	1,300,000,000
Letters of Credit Outstanding, Amount											0
Line of Credit Facility, Amount Outstanding									0	375,000,000
Additional amount credit facility can be increased.										400,000,000
Increased capacity of credit facility								400,000,000
Maximum ratio of debt to EBITDA							5.0
Maximum ratio of debt to EBITDA after acquisitions							5.5
Aggregate purchase price of acquistions increasing debt to EBITDA ratio							50,000,000
Maximum ratio of debt to capitalization	65.00%
LineOfCreditFacilityCommitmentFeePercentage	0.20%
Long-term Debt, by Current and Noncurrent [Abstract]
Debt Instrument, Face Amount				375,000,000	400,000,000	325,000,000
Debt Instrument, Interest Rate, Stated Percentage				5.40%	4.45%	8.875%
OperatingExpensesAbstract
LeaseAndRentalExpense	$ 10,900,000	$ 9,100,000	$ 9,300,000