Derivatives and Risk Management Activities - Financial Impact (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Impact of derivative activities recognized in earnings
Total gain (loss) on derivatives recognized in net income	$ 106	$ (198)	$ (324)
Supply and Logistics segment revenues
Impact of derivative activities recognized in earnings
Total gain (loss) on derivatives recognized in net income	127	(180)	(345)
Transportation segment revenues
Impact of derivative activities recognized in earnings
Total gain (loss) on derivatives recognized in net income			5
Field operating costs
Impact of derivative activities recognized in earnings
Total gain (loss) on derivatives recognized in net income	(2)	(10)
Depreciation and amortization
Impact of derivative activities recognized in earnings
Total gain (loss) on derivatives recognized in net income		(3)
Interest expense, net
Impact of derivative activities recognized in earnings
Total gain (loss) on derivatives recognized in net income	(5)	(18)	(14)
Other income/(expense), net
Impact of derivative activities recognized in earnings
Total gain (loss) on derivatives recognized in net income	(14)	13	30
Commodity Derivatives
Impact of derivative activities recognized in earnings
Total gain (loss) on derivatives recognized in net income	148	(201)	(337)
Foreign Currency Derivatives
Impact of derivative activities recognized in earnings
Total gain (loss) on derivatives recognized in net income	(23)	8	(3)
Preferred Distribution Rate Reset Option
Impact of derivative activities recognized in earnings
Total gain (loss) on derivatives recognized in net income	(14)	13	30
Interest Rate Derivatives
Impact of derivative activities recognized in earnings
Total gain (loss) on derivatives recognized in net income	(5)	(18)	(14)
Derivatives in Hedging Relationships | Commodity Derivatives | Depreciation and amortization
Impact of derivative activities recognized in earnings
Total gain (loss) on derivatives recognized in net income		(3)
Derivatives in Hedging Relationships | Commodity Derivatives | Interest expense, net
Impact of derivative activities recognized in earnings
Total gain (loss) on derivatives recognized in net income	0	0	0
Derivatives in Hedging Relationships | Foreign Currency Derivatives | Depreciation and amortization
Impact of derivative activities recognized in earnings
Total gain (loss) on derivatives recognized in net income		0
Derivatives in Hedging Relationships | Foreign Currency Derivatives | Interest expense, net
Impact of derivative activities recognized in earnings
Total gain (loss) on derivatives recognized in net income	0	0	0
Derivatives in Hedging Relationships | Preferred Distribution Rate Reset Option | Depreciation and amortization
Impact of derivative activities recognized in earnings
Total gain (loss) on derivatives recognized in net income		0
Derivatives in Hedging Relationships | Preferred Distribution Rate Reset Option | Interest expense, net
Impact of derivative activities recognized in earnings
Total gain (loss) on derivatives recognized in net income	0	0	0
Derivatives in Hedging Relationships | Interest Rate Derivatives | Depreciation and amortization
Impact of derivative activities recognized in earnings
Total gain (loss) on derivatives recognized in net income		0
Derivatives in Hedging Relationships | Interest Rate Derivatives | Interest expense, net
Impact of derivative activities recognized in earnings
Total gain (loss) on derivatives recognized in net income	(5)	(18)	(14)
Derivatives Not Designated as a Hedge | Commodity Derivatives | Supply and Logistics segment revenues
Impact of derivative activities recognized in earnings
Total gain (loss) on derivatives recognized in net income	150	(188)	(342)
Derivatives Not Designated as a Hedge | Commodity Derivatives | Transportation segment revenues
Impact of derivative activities recognized in earnings
Total gain (loss) on derivatives recognized in net income			5
Derivatives Not Designated as a Hedge | Commodity Derivatives | Field operating costs
Impact of derivative activities recognized in earnings
Total gain (loss) on derivatives recognized in net income	(2)	(10)
Derivatives Not Designated as a Hedge | Commodity Derivatives | Other income/(expense), net
Impact of derivative activities recognized in earnings
Total gain (loss) on derivatives recognized in net income	0	0	0
Derivatives Not Designated as a Hedge | Foreign Currency Derivatives | Supply and Logistics segment revenues
Impact of derivative activities recognized in earnings
Total gain (loss) on derivatives recognized in net income	(23)	8	(3)
Derivatives Not Designated as a Hedge | Foreign Currency Derivatives | Transportation segment revenues
Impact of derivative activities recognized in earnings
Total gain (loss) on derivatives recognized in net income			0
Derivatives Not Designated as a Hedge | Foreign Currency Derivatives | Field operating costs
Impact of derivative activities recognized in earnings
Total gain (loss) on derivatives recognized in net income	0	0
Derivatives Not Designated as a Hedge | Foreign Currency Derivatives | Other income/(expense), net
Impact of derivative activities recognized in earnings
Total gain (loss) on derivatives recognized in net income	0	0	0
Derivatives Not Designated as a Hedge | Preferred Distribution Rate Reset Option | Supply and Logistics segment revenues
Impact of derivative activities recognized in earnings
Total gain (loss) on derivatives recognized in net income	0	0	0
Derivatives Not Designated as a Hedge | Preferred Distribution Rate Reset Option | Transportation segment revenues
Impact of derivative activities recognized in earnings
Total gain (loss) on derivatives recognized in net income			0
Derivatives Not Designated as a Hedge | Preferred Distribution Rate Reset Option | Field operating costs
Impact of derivative activities recognized in earnings
Total gain (loss) on derivatives recognized in net income	0	0
Derivatives Not Designated as a Hedge | Preferred Distribution Rate Reset Option | Other income/(expense), net
Impact of derivative activities recognized in earnings
Total gain (loss) on derivatives recognized in net income	(14)	13	30
Derivatives Not Designated as a Hedge | Interest Rate Derivatives | Supply and Logistics segment revenues
Impact of derivative activities recognized in earnings
Total gain (loss) on derivatives recognized in net income	0	0	0
Derivatives Not Designated as a Hedge | Interest Rate Derivatives | Transportation segment revenues
Impact of derivative activities recognized in earnings
Total gain (loss) on derivatives recognized in net income			0
Derivatives Not Designated as a Hedge | Interest Rate Derivatives | Field operating costs
Impact of derivative activities recognized in earnings
Total gain (loss) on derivatives recognized in net income	0	0
Derivatives Not Designated as a Hedge | Interest Rate Derivatives | Other income/(expense), net
Impact of derivative activities recognized in earnings
Total gain (loss) on derivatives recognized in net income	$ 0	$ 0	0
Supply and Logistics | Derivatives Not Designated as a Hedge
Impact of derivative activities recognized in earnings
Total gain (loss) on derivatives recognized in net income			$ 2