Long-Term Debt and Credit Facility (Tables)

9 Months Ended

Sep. 30, 2012

Debt Disclosure [Abstract]

Summary of debt

	September 30,			December 31,
	2012			2011
	(In millions)
1.500% fixed-rate notes, due 2013	$	300		$	300
2.375% fixed-rate notes, due 2015	400			400
2.700% fixed-rate notes, due 2018	500			500
2.500% fixed-rate notes, due 2022	500			—
	$	1,700		$	1,200
Unaccreted discount	(7		)	(4		)
	$	1,693		$	1,196