Shareholders' Equity (Details) In Millions, except Share data, unless otherwise specified	1 Months Ended			3 Months Ended
	Jan. 31, 2012 USD ($)	Aug. 31, 2011 USD ($)	Nov. 30, 2010 USD ($)	Mar. 31, 2012 USD ($)	Mar. 31, 2012 CHF	Mar. 31, 2011 USD ($)	Mar. 31, 2011 CHF	Dec. 31, 2011
Shareholders' Equity [Abstract]
Per Common Share increase dividend installments	$ 0.12
Dividends declared per common share				$ 0.47	0.42	$ 0.33	0.30
Common shares in treasury, shares				4,179,030	4,179,030			5,905,136
Stock repurchase program, authorized amount		$ 303	$ 600
Repurchase of outstanding common shares, shares				100,000	100,000
Transaction cost				7.0
Share repurchase authorization remains		$ 197		$ 461