Shareholders' Equity (Details)	1 Months Ended				12 Months Ended
	Dec. 31, 2011 USD ($)	Dec. 31, 2011 CHF	May 31, 2009 CHF	Dec. 31, 2008 subsidiary	Dec. 31, 2011 USD ($) installment	Dec. 31, 2010 USD ($)	Dec. 31, 2010 CHF	May 31, 2011 USD ($) installment
Share issuance
Issuance of shares (in shares)	29,900,000	29,900,000		16,000,000
Price per share issued under public offering	$ 40.50	37.19
Share repurchase USD exchange rate	$ 1				$ 1
Share repurchase CHF average exchange rate		0.9183
Proceeds from issuance of shares, net of underwriting discounts and commissions, issuance costs and the Swiss Federal Issuance tax	1,211,000,000				1,211,000,000
Distribution of qualifying additional paid-in capital
Cash distribution approved in the form of additional paid-in capital (in dollars per share)								$ 3.16
Number of quarterly installments (in installments)								4
Amount of installment (in dollars per share)								$ 0.79
Number of quarterly installments paid					3
Installment of dividend paid					763,000,000
Unpaid distribution payable	278,000,000				278,000,000
Shares held by subsidiary
Number of issued shares to a subsidiary to satisfy obligations in connection with awards granted under incentive plans or other rights to acquire shares of stocks	29,900,000	29,900,000		16,000,000
Number of subsidiaries to whom shares were issued				1
Number of shares held by subsidiary	12,000,000	12,000,000			12,000,000	13,000,000	13,000,000
Share repurchase program
Authorized amount for repurchase of shares			3,500,000,000		3,700,000,000
Share repurchase USD exchange rate	1				1
Share repurchase CHF exchange rate		0.94
Treasury shares purchased under share repurchase program						2,863,267	2,863,267
Aggregate purchase price						$ 240,000,000	257,000,000
Treasury shares	2,863,267	2,863,267			2,863,267	2,863,267	2,863,267