Derivative and Hedging Activities Derivative and Hedging Activities, Marketing, Gathering and Compression Sales (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Derivative Instruments, Gain (Loss) [Line Items]
Marketing, Gathering and Compression Revenue	$ 2,305	$ 3,167	$ 3,980	$ 6,182
Marketing, Gathering And Compression [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Refining and Marketing Revenue	2,085	3,167	3,760	6,182
Other Contract [Member] | Marketing, Gathering And Compression [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Settlements	27		27
Fair Value, Inputs, Level 3 [Member] | Other Contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Settlements			0	0
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Gain (Loss) Included in Earnings		$ 0	220	$ 0
Fair Value, Inputs, Level 3 [Member] | Other Contract [Member] | Marketing, Gathering And Compression [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Gain (Loss) Included in Earnings	$ 220		$ 220