Debt, Financing Arrangements and Leases (Details) - USD ($)		1 Months Ended	12 Months Ended
	Apr. 15, 2016	Sep. 30, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Jan. 22, 2016	Feb. 02, 2015
Debt Instrument [Line Items]
Total long-term debt, including current portion			$ 2,463,426,000	$ 2,232,500,000
Other financing obligation			230,926,000	0
Unamortized debt issuance costs			(15,377,000)	(16,408,000)
Unamortized debt premium and discount, net			(5,043,000)	(5,338,000)
Long-term debt due within one year			251,430,000	0
Total long-term debt			2,191,576,000	2,210,754,000
Long-term Debt, Fiscal Year Maturity [Abstract]
2018			251,566,000
2019			1,721,000
2020			1,893,000
2021			2,081,000
2022			2,289,000
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
2018			13,558,000
2019			14,890,000
2020			14,860,000
2021			14,710,000
2022			14,654,000
Thereafter			122,333,000
Total net minimum obligations			195,005,000
Operating leases, rent expense			11,000,000	10,600,000	$ 10,700,000
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
Commercial paper			$ 0
6.4% due 2016 [Member]
Debt Instrument [Line Items]
Long-term debt interest rate	6.40%
Long-Term Debt, retired	$ 200,000,000
10% due 2052 [Member]
Debt Instrument [Line Items]
Long-term debt interest rate			10.00%
Dalton Expansion Project [Member]
Debt Instrument [Line Items]
Other financing obligation		$ 235,800,000
Long-term debt face amount			$ 229,400,000
Debt Instrument, Term		35 years
Debentures
Debt Instrument [Line Items]
Total long-term debt, including current portion			207,500,000	207,500,000
Debentures | 7.08% due 2026 [Member]
Debt Instrument [Line Items]
Total long-term debt, including current portion			7,500,000	7,500,000
Debentures | 7.25% due 2026 [Member]
Debt Instrument [Line Items]
Total long-term debt, including current portion			200,000,000	200,000,000
Notes
Debt Instrument [Line Items]
Total long-term debt, including current portion			2,025,000,000	2,025,000,000
Notes | 6.05% due 2018 [Member]
Debt Instrument [Line Items]
Total long-term debt, including current portion			250,000,000	250,000,000
Notes | 7.85% due 2026
Debt Instrument [Line Items]
Total long-term debt, including current portion			1,000,000,000	1,000,000,000
Long-term debt face amount						$ 1,000,000,000
Long-term debt interest rate						7.85%
Notes | 5.4% due 2041 [Member]
Debt Instrument [Line Items]
Total long-term debt, including current portion			375,000,000	375,000,000
Notes | 4.45% due 2042 [Member]
Debt Instrument [Line Items]
Total long-term debt, including current portion			400,000,000	$ 400,000,000
$3.5 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
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
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
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