Environmental Liabilities and Asset Retirement Obligations Environmental Liabilities (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013
Accrual for Environmental Loss Contingencies
Balance at beginning of year	$ 262	[1]	$ 85	[1]
Additions, net	59		50
Environmental Liabilities assumed with Acquisitions	12		170
Expenditures	(59)		(43)
Balance at end of year	274	[1]	262	[1]
Cost Share Arrangement Percent	75.00%
Environmental insurance coverage ceiling	190
Self insurance deductible	50
TLLP
Accrual for Environmental Loss Contingencies
Balance at beginning of year	24
Additions, net	28
Balance at end of year	32
Environmental insurance coverage ceiling	25
Martinez Refinery
Accrual for Environmental Loss Contingencies
Balance at end of year	216		216
Environmental accrual under cost-share agreement	$ 56

[1] Includes $32 million and $24 million of TLLP environmental liabilities at December 31, 2014 and 2013, respectively.