Debt and Financing Arrangements (Details Textual) (USD $)	Jul. 31, 2012	Jun. 30, 2012
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity		$ 400,000,000
Letters of Credit Outstanding, Amount		0
Line of Credit Facility, Amount Outstanding		345,000,000
$375 Million, 5.4% Senior Notes due 2041 [Member]
Long-term Debt, by Current and Noncurrent [Abstract]
Debt Instrument, Face Amount		375,000,000
Debt Instrument, Interest Rate, Stated Percentage		5.40%
$400 Million, 4.45% Senior Notes due 2042 [Member]
Long-term Debt, by Current and Noncurrent [Abstract]
Debt Instrument, Face Amount		400,000,000
Debt Instrument, Interest Rate, Stated Percentage		4.45%
Long-term Debt, Other Disclosures [Abstract]
Additional Interest Rate Accrued For Default Of Registration Rights Agreements First Period	0.25%
Additional Interest Rate Accrued For Default Of Registration Rights Agreements Each Subsequent Period	0.25%
MaximumAdditional Interest Rate Accrued For Default Of Registration Rights Agreements All Periods	0.50%
$325 Million, 8.875% Senior Notes due July 15, 2012 [Member]
Long-term Debt, by Current and Noncurrent [Abstract]
Debt Instrument, Face Amount		325,000,000
Debt Instrument, Interest Rate, Stated Percentage		8.875%
$2 billion unsecured credit facility [Member] | Williams Partners L.P. [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity		2,000,000,000
$2 billion unsecured credit facility [Member] | Williams Partners L.P. [Member] | Letter of Credit [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity		$ 1,300,000,000