Property, Net Of Accumulated Depreciation (Narrative) (Details) (USD $)	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Dec. 31, 2011
Property, Net Of Accumulated Depreciation [Abstract]
Interest costs capitalized as part of property, net	$ 21,000,000	$ 7,000,000
Precious metals	2,400,000,000		2,500,000,000
Depletion expense	$ 5,000,000	$ 4,000,000