Contingencies And Commitments (Narrative) (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	9 Months Ended
	Sep. 30, 2011	Jul. 11, 2011
Sundrop Fuels, Inc. [Member]
Sale Leaseback Transaction [Line Items]
Investment in preferred stock of Sundrop Fuels Inc	$ 155	$ 35
Clean Energy Fuels Corp. [Member]
Sale Leaseback Transaction [Line Items]
Investment in newly issued convertible notes	50	150
Debt Conversion, Converted Instrument, Rate	22.50%
Conversion price for convertible promissory note	$ 15.80
Annual rate	7.50%
Minimum [Member] | Rig Leases [Member]
Sale Leaseback Transaction [Line Items]
Entered into a master lease agreement under which we agreed to leaseback from the buyer, minimum term (in years)	5
Minimum [Member] | Drilling Contracts Rights [Member]
Sale Leaseback Transaction [Line Items]
Contract lease terms (in years)	4
Maximum [Member] | Rig Leases [Member]
Sale Leaseback Transaction [Line Items]
Entered into a master lease agreement under which we agreed to leaseback from the buyer, maximum term (in years)	10
Maximum [Member] | Drilling Contracts Rights [Member]
Sale Leaseback Transaction [Line Items]
Contract lease terms (in years)	3
Rig Leases [Member]
Sale Leaseback Transaction [Line Items]
Entered into a master lease agreement under which we agreed to leaseback from the buyer, proceeds from sale	802
Entered into a master lease agreement under which we agreed to leaseback from the buyer, minimum aggregate future lease payments	481
Equipment sold	93
Number of repurchased equipment	1
Compressor Leases [Member]
Sale Leaseback Transaction [Line Items]
Entered into a master lease agreement under which we agreed to leaseback from the buyer, proceeds from sale	635
Entered into a master lease agreement under which we agreed to leaseback from the buyer, minimum term (in years)	4
Entered into a master lease agreement under which we agreed to leaseback from the buyer, maximum term (in years)	10
Entered into a master lease agreement under which we agreed to leaseback from the buyer, minimum aggregate future lease payments	496
Equipment sold	2,542
Number of repurchased equipment	6
Drilling Contracts Rights [Member]
Sale Leaseback Transaction [Line Items]
Number of drilling rigs leased	64
Future minimum undiscounted aggregate drilling commitment	$ 494