Shareholder's Equity - Additional Information (Detail) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2015 USD ($) $ / shares shares	Dec. 31, 2014 SFr / shares $ / shares	Dec. 31, 2013 $ / shares	Dec. 31, 2014 USD ($) shares
Shareholders Equity
Common stock, shares authorized | shares	426.0			426.0
Common stock, par value (per share) | (per share)	$ 0.01	SFr 0.01
Common stock shares repurchased, shares | shares	3.1
Common stock amount repurchased	$ 200.0
Dividends payable amount per share | $ / shares	$ 0.33
ApprovedNotDeclaredlDividends | $ / shares	$ 1.34
Dividends payable	$ 59.6			$ 116.8
Dividends paid per common share | $ / shares	$ 1.28	SFr 1.10	$ 0.96
Treasury Stock, Shares, Retired | shares	19.1
September 2012 Share Repurchase Program
Shareholders Equity
Authorized amount to repurchase shares of common stock	$ 400.0
2012 Share Repurchase Programs [Member]
Shareholders Equity
Authorized amount to repurchase shares of common stock	1,200.0
October 2012 Share Repurchase Program
Shareholders Equity
Authorized amount to repurchase shares of common stock	$ 800.0
Authorization expiry date	Dec. 31, 2015
December 2013 Share Repurchase Program
Shareholders Equity
Authorized amount to repurchase shares of common stock	$ 1,000.0
Remaining authorized repurchase amount	$ 800.0
Authorization expiry date	Dec. 31, 2016
December 2014 Share Repurchase Program [Member] [Domain]
Shareholders Equity
Authorized amount to repurchase shares of common stock	$ 1,000.0
Treasury Stock [Member]
Shareholders Equity
Treasury Stock, Retired, Cost Method, Amount	$ 1,210.9
First Quarter [Member]
Shareholders Equity
ApprovedNotDeclaredlDividends | $ / shares	$ 0.33
First Quarter [Member]
Shareholders Equity
ApprovedNotDeclaredlDividends | $ / shares	0.33
Third Quarter [Member]
Shareholders Equity
ApprovedNotDeclaredlDividends | $ / shares	0.34
First Quarter [Member]
Shareholders Equity
ApprovedNotDeclaredlDividends | $ / shares	$ 0.34