Derivatives and Risk Management Activities (Details 4) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Impact of derivative activities recognized in earnings
Total	$ 29	$ 48	$ 183	$ (147)
Commodity | Supply and Logistics segment revenues
Impact of derivative activities recognized in earnings
Total	21	49	121	(147)
Commodity | Facilities segment revenues
Impact of derivative activities recognized in earnings
Total		3	13	(2)
Commodity | Purchases and related costs
Impact of derivative activities recognized in earnings
Total			41	(1)
Commodity | Field Operating costs
Impact of derivative activities recognized in earnings
Total	4	(1)	2
Interest Rate Contracts | Interest expense
Impact of derivative activities recognized in earnings
Total	(1)		(2)	1
Net gain associated with interest rate swaps designated as fair value hedges			2	1
Foreign exchange contracts | Supply and Logistics segment revenues
Impact of derivative activities recognized in earnings
Total	4	(6)	4	(3)
Foreign exchange contracts | Other income/(expense), net
Impact of derivative activities recognized in earnings
Total	1	3	4	5
Derivatives designated as hedging instruments
Impact of derivative activities recognized in earnings
Total	123	5	118	(234)
Derivatives in Cash Flow Hedging Relationships - Ineffective Portion		8	(2)
Derivatives designated as hedging instruments | Commodity | Supply and Logistics segment revenues
Impact of derivative activities recognized in earnings
Total	123	(1)	62	(237)
Derivatives designated as hedging instruments | Commodity | Facilities segment revenues
Impact of derivative activities recognized in earnings
Total		3	13	(3)
Derivatives designated as hedging instruments | Commodity | Purchases and related costs
Impact of derivative activities recognized in earnings
Total			41
Derivatives designated as hedging instruments | Interest Rate Contracts | Interest expense
Impact of derivative activities recognized in earnings
Total	(1)		(2)	1
Derivatives designated as hedging instruments | Foreign exchange contracts | Other income/(expense), net
Impact of derivative activities recognized in earnings
Total	1	3	4	5
Derivatives not designated as hedging instruments
Impact of derivative activities recognized in earnings
Total	(94)	43	65	87
Derivatives not designated as hedging instruments | Commodity | Supply and Logistics segment revenues
Impact of derivative activities recognized in earnings
Total	(102)	50	59	90
Derivatives not designated as hedging instruments | Commodity | Facilities segment revenues
Impact of derivative activities recognized in earnings
Total				1
Derivatives not designated as hedging instruments | Commodity | Purchases and related costs
Impact of derivative activities recognized in earnings
Total				(1)
Derivatives not designated as hedging instruments | Commodity | Field Operating costs
Impact of derivative activities recognized in earnings
Total	4	(1)	2
Derivatives not designated as hedging instruments | Foreign exchange contracts | Supply and Logistics segment revenues
Impact of derivative activities recognized in earnings
Total	$ 4	$ (6)	$ 4	$ (3)