Debt - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	1 Months Ended		1 Months Ended									12 Months Ended
	Sep. 30, 2011	Dec. 20, 2010	Dec. 15, 2010 Accelerated Share Repurchase Agreement	Sep. 30, 2011 Retained Earnings	Dec. 31, 2013 1.375% Notes Due 2018	Oct. 30, 2012 1.375% Notes Due 2018	Dec. 31, 2013 2.875% Notes Due 2016	Dec. 20, 2010 2.875% Notes Due 2016	Dec. 31, 2013 4.40% Notes Due 2021	Dec. 20, 2010 4.40% Notes Due 2021	Dec. 31, 2013 6.70% Notes Due 2026	Dec. 31, 2013 Five Year Syndicated Credit Facility Prior To September 2013 Amendment	Dec. 31, 2013 Five Year Syndicated Credit Facility After September 2013 Amendment
Debt Instrument [Line Items]
Senior unsecured notes - aggregate principal amount		$ 750				$ 500		$ 250		$ 500
Debt instrument interest rate					1.375%	1.375%	2.875%	2.875%	4.40%	4.40%	6.70%
Debt instrument maturity date					2018	2018	2016	2016	2021	2021	2026
ASR agreement with the bank to repurchase outstanding common stock			750
Cash remitted to bank counterparty upon final settlement under the ASR agreement	58.9
Decrease to shareholder's investment				69.1
Increase of capital in excess of par value	10.2
Line of credit facility, borrowing capacity												$ 600	$ 750
Line of credit facility, term, in years												5 years
Line of credit facility, expiration date												2016-10	2018-09