Supplemental Cash Flow Information (Tables)

12 Months Ended

Dec. 31, 2011

Supplemental Cash Flow Information [Abstract]

Supplemental Cash Flow Information

	Year Ended December 31,
	2011		2010		2009
	(in millions)
Interest paid on outstanding debt	$	238	$	233	$	237
Income tax payments		273		341		387
Income tax refunds		18		12		13