Derivatives and Risk Management Activities (Details 4) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Impact of derivative activities recognized in earnings
Total	$ 153	$ (41)	$ 124
Commodity Derivatives | Supply and Logistics segment revenues
Impact of derivative activities recognized in earnings
Total	205	(39)	72
Commodity Derivatives | Facilities segment revenues
Impact of derivative activities recognized in earnings
Total		(11)	3
Commodity Derivatives | Purchases and related costs
Impact of derivative activities recognized in earnings
Total			46
Commodity Derivatives | Field Operating costs
Impact of derivative activities recognized in earnings
Total	(21)	8	1
Interest Rate Derivatives | Interest expense
Impact of derivative activities recognized in earnings
Total	(5)	(4)	(3)
Foreign Currency Derivatives | Supply and Logistics segment revenues
Impact of derivative activities recognized in earnings
Total	(28)		(1)
Foreign Currency Derivatives | Other income/(expense), net
Impact of derivative activities recognized in earnings
Total	2	5	6
Derivatives in Hedging Relationships
Impact of derivative activities recognized in earnings
Gain/(loss) reclassified from AOCI into income	(4)	66	62
Other gain/(loss) recognized in income		1
Derivatives in Hedging Relationships | Supply and Logistics segment revenues
Impact of derivative activities recognized in earnings
Gain/(loss) reclassified from AOCI into income	7
Derivatives in Hedging Relationships | Commodity Derivatives | Supply and Logistics segment revenues
Impact of derivative activities recognized in earnings
Gain/(loss) reclassified from AOCI into income	(1)	78	12
Other gain/(loss) recognized in income		(1)
Derivatives in Hedging Relationships | Commodity Derivatives | Facilities segment revenues
Impact of derivative activities recognized in earnings
Gain/(loss) reclassified from AOCI into income		(10)	3
Other gain/(loss) recognized in income		(1)	(1)
Derivatives in Hedging Relationships | Commodity Derivatives | Purchases and related costs
Impact of derivative activities recognized in earnings
Gain/(loss) reclassified from AOCI into income			45
Derivatives in Hedging Relationships | Interest Rate Derivatives | Interest expense
Impact of derivative activities recognized in earnings
Gain/(loss) reclassified from AOCI into income	(5)	(7)	(4)
Other gain/(loss) recognized in income		3	1
Derivatives in Hedging Relationships | Foreign Currency Derivatives | Other income/(expense), net
Impact of derivative activities recognized in earnings
Gain/(loss) reclassified from AOCI into income	2	5	6
Derivatives in Hedging Relationships | Hedged Transactions probable of not occurring | Supply and Logistics segment revenues
Impact of derivative activities recognized in earnings
Gain/(loss) reclassified from AOCI into income		3
Derivatives in Hedging Relationships | Hedged Transactions probable of not occurring | Facilities segment revenues
Impact of derivative activities recognized in earnings
Gain/(loss) reclassified from AOCI into income		(1)
Derivatives Not Designated as a Hedge
Impact of derivative activities recognized in earnings
Total	157	(108)	62
Derivatives Not Designated as a Hedge | Commodity Derivatives | Supply and Logistics segment revenues
Impact of derivative activities recognized in earnings
Total	206	(116)	60
Derivatives Not Designated as a Hedge | Commodity Derivatives | Facilities segment revenues
Impact of derivative activities recognized in earnings
Total			1
Derivatives Not Designated as a Hedge | Commodity Derivatives | Purchases and related costs
Impact of derivative activities recognized in earnings
Total			1
Derivatives Not Designated as a Hedge | Commodity Derivatives | Field Operating costs
Impact of derivative activities recognized in earnings
Total	(21)	8	1
Derivatives Not Designated as a Hedge | Foreign Currency Derivatives | Supply and Logistics segment revenues
Impact of derivative activities recognized in earnings
Total	$ (28)		$ (1)