Income Taxes (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Income Taxes
Effective tax rate, continuing operations (as a percent)	28.70%	34.80%	29.90%	31.70%
Effective tax rate, favorable impact of recognition of deferred U.S. tax benefit primarily attributable to foreign earnings in South Africa				$ 16