Supplemental Disclosures Of Cash Flow Information (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 30, 2014		Sep. 30, 2013		Sep. 30, 2014		Sep. 30, 2013
Supplemental Disclosures Of Cash Flow Information [Abstract]
Cash paid for interest	$ 45	[1]	$ 45	[1]	$ 95	[1]	$ 95	[1]
Cash paid for income taxes			1				19
Noncash property and equipment changes	57		(12)		128		34
Interest paid, capitalized	$ 14		$ 15		$ 40		$ 48

[1] Cash paid for interest includes capitalized interest of $14 million and $15 million for the three months ended September 30, 2014 and 2013, respectively, and capitalized interest of $40 million and $48 million for the nine months ended September 30, 2014 and 2013, respectively.