Fair Value Measurements (Details 1) (USD $) In Millions	3 Months Ended	6 Months Ended
Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Fair Value Measurements Using Significant Unobservable Inputs
Beginning balance	$ 0	$ 5	$ 1	$ 2
Realized and unrealized gains (losses):
Included in income (loss) from continuing operations	3	(1)	2	(1)
Included in other comprehensive income (loss)		11	(1)	15
Settlements	(2)	(1)	(2)	(2)
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	1
Ending balance	1	14	1	14
Unrealized gains (losses) included in income (loss) from continuing operations relating to instruments still held at June 30	$ 1	$ (1)		$ (1)

This item represents the amount of the total realized and unrealized gains or losses for the period which are included in the statement of income (or changes in net assets); the fair value of which assets and liabilities was or is measured on a recurring basis using significant unobservable inputs (Level 3).

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=6925170&loc=d3e19207-110258

+ Details

Name:	us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisGainLossIncludedInEarnings
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

Name:	us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationAbstract
Namespace Prefix:	us-gaap
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

This element represents total gains (losses) for the period (realized and unrealized), arising from assets and liabilities measured at fair value on a recurring basis using unobservable inputs (Level 3), which are included in other comprehensive income (a separate component of shareholders' equity).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(1)
-SubTopic 10
-Topic 820
-URI http://asc.fasb.org/extlink&oid=6925170&loc=d3e19207-110258

+ Details

Name:	us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetAndLiabilityGainLossIncludedInOtherComprehensiveIncomeLoss
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

This element represents an asset measured at fair value using significant unobservable inputs (Level 3) which is required for reconciliation purposes of beginning and ending balances.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 157
-Paragraph 32
-Subparagraph c
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=6925170&loc=d3e19207-110258

+ Details

Name:	us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Liability Settlements.

+ Details

Name:	wmb_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetLiabilitySettlements
Namespace Prefix:	wmb
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Realized and unrealized gains losses.

+ Details

Name:	wmb_RealizedAndUnrealizedGainsLossesAbstract
Namespace Prefix:	wmb
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Transfers into Level 3.

+ Details

Name:	wmb_TransfersIntoLevel3
Namespace Prefix:	wmb
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Transfers out of Level 3.

+ Details

Name:	wmb_TransfersOutOfLevel3
Namespace Prefix:	wmb
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Unrealized gains Losses Included In Income Loss From Continuing Operations Relating To Instruments Held At Period End.

+ Details

Name:	wmb_UnrealizedGainsLossesIncludedInIncomeLossFromContinuingOperationsRelatingToInstrumentsHeldAtPeriodEnd
Namespace Prefix:	wmb
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration