Fair Value Measurements Nonrecurring Measurements (Details) - USD ($) $ in Millions		3 Months Ended									9 Months Ended
		Sep. 30, 2016	Jun. 30, 2016		Mar. 31, 2016		Sep. 30, 2015		Jun. 30, 2015	[3]	Sep. 30, 2016	Sep. 30, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impairment of long-lived assets		$ 1					$ 2				$ 811	$ 29
Impairment of equity-method investments		$ 0					461				112	461
Impairment Of Long Lived Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impairment of long-lived assets											811	29
Impairment Of Equity-Method Investments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impairment of equity-method investments											112	461
Impairment Of Equity-Method Investments [Member] | Williams Partners [Member] | Delaware Basin Gas Gathering System [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impairment of equity-method investments							458				59	458
Impairment Of Equity-Method Investments [Member] | Williams Partners [Member] | Appalachia Midstream Investments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impairment of equity-method investments							3					3
Fair Value, Measurements, Nonrecurring [Member] | Impairment Of Long Lived Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impairment of long-lived assets	[1]										16	9
Fair Value, Measurements, Nonrecurring [Member] | Level 3 [Member] | Property Plant And Equipment, net [Member] | Williams Partners [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Property, Plant, and Equipment, Fair Value Disclosure			$ 18	[2]					$ 17
Fair Value, Measurements, Nonrecurring [Member] | Level 3 [Member] | Assets held for sale [Member] | Williams Partners [Member] | Canadian Operations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets Held-for-sale, Fair Value Disclosure	[4]		924
Fair Value, Measurements, Nonrecurring [Member] | Level 3 [Member] | Assets held for sale [Member] | Williams NGL & Petchem Services [Member] | Canadian Operations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets Held-for-sale, Fair Value Disclosure	[4]		206
Fair Value, Measurements, Nonrecurring [Member] | Level 3 [Member] | Investments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment, Fair Value Disclosure					$ 0
Fair Value, Measurements, Nonrecurring [Member] | Level 3 [Member] | Investments [Member] | Williams Partners [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment, Fair Value Disclosure					$ 1,294	[5]	$ 1,203	[6]				1,203	[6]
Fair Value, Measurements, Nonrecurring [Member] | Level 3 [Member] | Investments [Member] | Williams Partners [Member] | Minimum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value Inputs, Discount Rate					13.00%
Fair Value, Measurements, Nonrecurring [Member] | Level 3 [Member] | Investments [Member] | Williams Partners [Member] | Maximum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value Inputs, Discount Rate					13.30%
Fair Value, Measurements, Nonrecurring [Member] | Level 3 [Member] | Investments [Member] | Williams Partners [Member] | Delaware Basin Gas Gathering System [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value Inputs, Discount Rate							11.80%
Fair Value, Measurements, Nonrecurring [Member] | Level 3 [Member] | Investments [Member] | Williams Partners [Member] | Appalachia Midstream Investments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value Inputs, Discount Rate							8.80%
Fair Value, Measurements, Nonrecurring [Member] | Level 3 [Member] | Impairment Of Long Lived Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impairment of long-lived assets											$ 795	$ 20
Fair Value, Measurements, Nonrecurring [Member] | Level 3 [Member] | Impairment Of Long Lived Assets [Member] | Williams Partners [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impairment of long-lived assets			48	[2]					$ 20
Fair Value, Measurements, Nonrecurring [Member] | Level 3 [Member] | Impairment Of Long Lived Assets [Member] | Williams Partners [Member] | Canadian Operations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Disposal Group, Not Discontinued Operation, Impairment loss on classification to AHFS	[4]		341
Fair Value, Measurements, Nonrecurring [Member] | Level 3 [Member] | Impairment Of Long Lived Assets [Member] | Williams NGL & Petchem Services [Member] | Canadian Operations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Disposal Group, Not Discontinued Operation, Impairment loss on classification to AHFS	[4]		$ 406
Fair Value, Measurements, Nonrecurring [Member] | Level 3 [Member] | Impairment Of Equity-Method Investments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impairment of equity-method investments					$ 3
Fair Value, Measurements, Nonrecurring [Member] | Level 3 [Member] | Impairment Of Equity-Method Investments [Member] | Williams Partners [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impairment of equity-method investments					$ 109	[5]	$ 461	[6]

[1] Reflects multiple individually insignificant impairments of other certain assets that may no longer be in use or are surplus in nature for which the fair value was determined to be zero or an insignificant salvage value.

[2] Relates to certain gathering assets within the Mid-Continent region. The estimated fair value was determined by a market approach based on our analysis of observable inputs in the principal market.

[3] Relates to certain surplus equipment. The estimated fair value was determined by a market approach based on our analysis of observable inputs in the principal market.

[4] Relates to our Canadian operations. We designated these operations as held for sale as of June 30, 2016. As a result, we measured the fair value of the disposal group, resulting in an impairment charge. The estimated fair value was determined by a market approach based primarily on inputs received in the marketing process and reflects our estimate of the potential assumed proceeds. We disposed of our Canadian operations through a sale during the third quarter of 2016. See Note 2 – Divestiture.

[5] Relates to Williams Partners’ equity-method investments in DBJV and Laurel Mountain. Our carrying values in these equity-method investments had been written down to fair value at December 31, 2015. Our first-quarter 2016 analysis reflected higher discount rates for both of these investments, along with lower natural gas prices for Laurel Mountain. We estimated the fair value of these investments using an income approach based on expected future cash flows and appropriate discount rates. The determination of estimated future cash flows involved significant assumptions regarding gathering volumes and related capital spending. Discount rates utilized ranged from 13.0 percent to 13.3 percent and reflected increases in our cost of capital, revised estimates of expected future cash flows, and risks associated with the underlying businesses.

[6] Relates to Williams Partners’ equity-method investments in DBJV and certain of the Appalachia Midstream Investments. The historical carrying value of these investments was initially recorded based on estimated fair value during the third quarter of 2014 in conjunction with our acquisition of ACMP. We estimated the fair value of these investments using an income approach based on expected future cash flows and appropriate discount rates. The determination of estimated future cash flows involved significant assumptions regarding gathering volumes and related capital spending. Discount rates utilized were 11.8 percent and 8.8 percent for DBJV and certain of the Appalachia Midstream Investments, respectively, and reflected our cost of capital as impacted by market conditions, and risks associated with the underlying businesses.