Debt, Financing Arrangements and Leases (Details) (USD $)	12 Months Ended			0 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Feb. 02, 2015
Debt Instrument [Line Items]
Total long-term debt issues	$ 1,432,500,000	$ 1,432,500,000
Unamortized debt premium and discount	(4,005,000)	(4,145,000)
Total long-term debt, less current maturities	1,428,495,000	1,428,355,000
Long-term Debt, Fiscal Year Maturity [Abstract]
2015	0
2016: 6.4% Notes	200,000,000
2017	0
2018: 6.05% Notes	250,000,000
2019	0
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
2015	10,544,000
2016	10,567,000
2017	10,501,000
2018	10,480,000
2019	10,482,000
Thereafter	13,407,000
Total net minimum obligations	65,981,000
Operating leases, rent expense	11,100,000	11,400,000	10,900,000
Williams Partners L.P. [Member]
Line of Credit Facility [Line Items]
Commercial paper	798,000,000
$2.5 billion credit facility [Member] | Williams Partners L.P. [Member]
Line of Credit Facility [Line Items]
Letters of credit outstanding, amount	0
Line of credit facility, amount outstanding	0
Subsequent Event [Member] | Williams Partners L.P. [Member]
Line of Credit Facility [Line Items]
Line of credit facility, maximum borrowing capacity				3,500,000,000
Additional amount by which credit facility can be increased				500,000,000
Line of Credit Facility, Remaining Borrowing Capacity				500,000,000
Debt to EBITDA, ratio				5.0
Debt to EBITDA, after acquisitions, ratio				5.5
Maximum Ratio Of Debt To Capitalization				65.00%
Subsequent Event [Member] | Williams Partners L.P. [Member] | Rate addition to federal funds effective rate [Member]
Line of Credit Facility [Line Items]
Line of credit facility, basis spread on variable rate				0.50%
Subsequent Event [Member] | Williams Partners L.P. [Member] | Rate addition to London interbank offered rate (LIBOR) [Member]
Line of Credit Facility [Line Items]
Line of credit facility, basis spread on variable rate				1.00%
Subsequent Event [Member] | Swing Line Advances [Member] | Williams Partners L.P. [Member]
Line of Credit Facility [Line Items]
Line of credit facility, maximum borrowing capacity				150,000,000
Subsequent Event [Member] | Commercial paper [Member] | Williams Partners L.P. [Member]
Line of Credit Facility [Line Items]
Line of credit facility, maximum borrowing capacity				3,000,000,000
Subsequent Event [Member] | Letter of Credit [Member] | Williams Partners L.P. [Member]
Line of Credit Facility [Line Items]
Line of credit facility, maximum borrowing capacity				1,125,000,000
Debentures
Debt Instrument [Line Items]
Total long-term debt issues	207,500,000	207,500,000
Debentures | 7.08% due 2026 [Member]
Debt Instrument [Line Items]
Total long-term debt issues	7,500,000	7,500,000
Debentures | 7.25% due 2026 [Member]
Debt Instrument [Line Items]
Total long-term debt issues	200,000,000	200,000,000
Notes
Debt Instrument [Line Items]
Total long-term debt issues	1,225,000,000	1,225,000,000
Notes | 6.4% due 2016 [Member]
Debt Instrument [Line Items]
Total long-term debt issues	200,000,000	200,000,000
Notes | 6.05% due 2018 [Member]
Debt Instrument [Line Items]
Total long-term debt issues	250,000,000	250,000,000
Notes | 5.4% due 2041 [Member]
Debt Instrument [Line Items]
Total long-term debt issues	375,000,000	375,000,000
Notes | 4.45% due 2042 [Member]
Debt Instrument [Line Items]
Total long-term debt issues	$ 400,000,000	$ 400,000,000