Fair Value Measurements, Reconciliation (Details) (Fair Value, Measurements, Recurring [Member], USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Investments of Certain Benefit Plans [Member]
Reconciliation of Balances for Fair Value Measurements Developed Using Significant Unobservable Inputs Rollforward
Balance at beginning of year	$ 10	$ 10	$ 0
Purchases	1	0	0
Settlements	0	0	0
Total losses included in income	0	0	0
Transfers in and/or out of Level 3	0	0	10
Balance at end of year	11	10	10
The amount of total losses included in income attributable to the change in unrealized losses relating to assets still held at end of period	0	0	0
Other Investments [Member]
Reconciliation of Balances for Fair Value Measurements Developed Using Significant Unobservable Inputs Rollforward
Balance at beginning of year	0	0	0
Purchases	21	1	0
Settlements	0	0	0
Total losses included in income	(21)	(1)	0
Transfers in and/or out of Level 3	0	0	0
Balance at end of year	0	0	0
The amount of total losses included in income attributable to the change in unrealized losses relating to assets still held at end of period	(21)	(1)	0
Alon Earn Out Agreement [Member]
Reconciliation of Balances for Fair Value Measurements Developed Using Significant Unobservable Inputs Rollforward
Balance at beginning of year	0	0	13
Purchases	0	0	0
Settlements	0	0	(33)
Total losses included in income	0	0	20
Transfers in and/or out of Level 3	0	0	0
Balance at end of year	0	0	0
The amount of total losses included in income attributable to the change in unrealized losses relating to assets still held at end of period	$ 0	$ 0	$ 0