Impairment (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Dec. 31, 2011
Impairment (Textual)
Long-lived assets, carrying value	$ 25,155		$ 25,177
Asset impairment loss	611	0
Aruba Refinery [Member]
Impairment (Textual)
Non-binding purchase offer	350
Long-lived assets, fair value	350
Long-lived assets, carrying value	945
Asset impairment loss	$ 595