Business Segment Information (Details 1) (USD $) In Millions, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2010	Jun. 30, 2010	Mar. 31, 2010	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Disclosure on Geographic Areas, Revenue and Long Lived Assets
Revenues	$ 1,531	$ 1,372	$ 1,426	$ 1,295	$ 1,340	$ 1,255	$ 1,289	$ 1,187	$ 5,624	$ 5,071	$ 4,696
Long-Lived Assets	3,529				3,635				3,529	3,635
United States [Member]
Disclosure on Geographic Areas, Revenue and Long Lived Assets
Revenues									3,561	3,312	3,387
Long-Lived Assets	2,023				2,186				2,023	2,186
All other international [Member]
Disclosure on Geographic Areas, Revenue and Long Lived Assets
Revenues									2,063	1,599	1,137
Long-Lived Assets	$ 1,506				$ 1,125				$ 1,506	$ 1,125