Business Segments (Schedule Of Revenue And Long-Lived Assets, By Geographical Area) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended										12 Months Ended
	Dec. 31, 2012		Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011		Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Revenues from External Customers and Long-Lived Assets [Line Items]
Consolidated revenue	$ 5,695		$ 6,722	$ 3,577	$ 3,630	$ 3,368		$ 3,964	$ 3,534	$ 3,663	$ 19,624		$ 14,529		$ 14,272
Consolidated long-lived assets	81,611					48,532					81,611		48,532		45,487
U.S. [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Consolidated revenue											18,078		13,062		13,068
Consolidated long-lived assets	79,144					45,920					79,144		45,920		42,754
Latin America [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Consolidated revenue											1,546		1,467		1,204
Consolidated long-lived assets	$ 2,467	[1]				$ 2,612	[1]				$ 2,467	[1]	$ 2,612	[1]	$ 2,733	[1]

[1] Change in amounts of long-lived assets in Latin America includes foreign currency translation adjustments on property, plant and equipment and other long-lived asset balances.