Derivatives and Risk Management Activities (Details 4) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Impact of derivative activities recognized in earnings
Total	$ 20	$ 29	$ 100	$ 183
Commodity | Supply and Logistics segment revenues
Impact of derivative activities recognized in earnings
Total	18	21	105	121
Commodity | Facilities segment revenues
Impact of derivative activities recognized in earnings
Total	(2)		(14)	13
Commodity | Purchases and related costs
Impact of derivative activities recognized in earnings
Total				41
Commodity | Field Operating costs
Impact of derivative activities recognized in earnings
Total	2	4	7	2
Interest Rate Contracts | Interest expense
Impact of derivative activities recognized in earnings
Total	1	(1)	(2)	(2)
Foreign exchange contracts | Supply and Logistics segment revenues
Impact of derivative activities recognized in earnings
Total		4		4
Foreign exchange contracts | Other income, net
Impact of derivative activities recognized in earnings
Total	1	1	4	4
Derivatives designated as hedging instruments
Impact of derivative activities recognized in earnings
Amount of gain/(loss) reclassified from AOCI into income	106	123	124	120
Other gain/(loss) recognized in income	3		3	(2)
Derivatives designated as hedging instruments | Commodity | Supply and Logistics segment revenues
Impact of derivative activities recognized in earnings
Amount of gain/(loss) reclassified from AOCI into income	109	123	139	62
Derivatives designated as hedging instruments | Commodity | Facilities segment revenues
Impact of derivative activities recognized in earnings
Amount of gain/(loss) reclassified from AOCI into income	(2)		(14)	14
Other gain/(loss) recognized in income				(1)
Derivatives designated as hedging instruments | Commodity | Purchases and related costs
Impact of derivative activities recognized in earnings
Amount of gain/(loss) reclassified from AOCI into income				41
Derivatives designated as hedging instruments | Interest Rate Contracts | Interest expense
Impact of derivative activities recognized in earnings
Amount of gain/(loss) reclassified from AOCI into income	(2)	(1)	(5)	(1)
Other gain/(loss) recognized in income	3		3	(1)
Derivatives designated as hedging instruments | Foreign exchange contracts | Other income, net
Impact of derivative activities recognized in earnings
Amount of gain/(loss) reclassified from AOCI into income	1	1	4	4
Derivatives designated as hedging instruments | Hedged Transactions no longer probable | Supply and Logistics segment revenues
Impact of derivative activities recognized in earnings
Other gain/(loss) recognized in income			3
Derivatives designated as hedging instruments | Hedged Transactions no longer probable | Facilities segment revenues
Impact of derivative activities recognized in earnings
Other gain/(loss) recognized in income	(2)		(1)
Derivatives not designated as hedging instruments
Impact of derivative activities recognized in earnings
Total	(89)	(94)	(27)	65
Derivatives not designated as hedging instruments | Commodity | Supply and Logistics segment revenues
Impact of derivative activities recognized in earnings
Total	(91)	(102)	(34)	59
Derivatives not designated as hedging instruments | Commodity | Field Operating costs
Impact of derivative activities recognized in earnings
Total	2	4	7	2
Derivatives not designated as hedging instruments | Foreign exchange contracts | Supply and Logistics segment revenues
Impact of derivative activities recognized in earnings
Total		$ 4		$ 4