Equity (Details) SFr / shares in Units, $ / shares in Units, shares in Millions, SFr in Millions, $ in Millions	1 Months Ended								3 Months Ended																12 Months Ended
	Mar. 31, 2015 installment SFr / shares	Mar. 31, 2015 installment $ / shares	Mar. 31, 2014 installment SFr / shares	Mar. 31, 2014 installment $ / shares	Mar. 31, 2013 installment SFr / shares	Mar. 31, 2013 installment $ / shares	Mar. 30, 2012 installment SFr / shares	Mar. 30, 2012 installment SFr / shares $ / shares	Mar. 25, 2016 $ / shares	Dec. 25, 2015 $ / shares	Sep. 25, 2015 CHF (SFr) SFr / shares $ / shares shares	Jun. 26, 2015 $ / shares	Mar. 27, 2015 $ / shares	Dec. 26, 2014 $ / shares	Sep. 26, 2014 CHF (SFr) SFr / shares $ / shares shares	Jun. 27, 2014 $ / shares	Mar. 28, 2014 $ / shares	Dec. 27, 2013 $ / shares	Sep. 27, 2013 $ / shares	Jun. 28, 2013 $ / shares	Mar. 29, 2013 SFr / shares $ / shares	Dec. 28, 2012 $ / shares	Sep. 28, 2012 $ / shares	Jun. 29, 2012 $ / shares	Sep. 25, 2015 USD ($) $ / shares shares	Sep. 26, 2014 USD ($) $ / shares shares	Sep. 27, 2013 USD ($) $ / shares shares	Sep. 25, 2015 USD ($) shares	Sep. 26, 2014 USD ($) shares	Mar. 29, 2013 $ / shares	Mar. 30, 2012 installment $ / shares
Equity
Maximum percentage of shares that the board may authorize for issuance																									50.00%
Common shares held in treasury											20				11													20	11
Common shares held in treasury, owned by subsidiary											6				9													6	9
Cancellation of treasury shares (in shares)																									5	10	10
Contributed surplus established during the change of domicile for Swiss tax and statutory purposes ("Swiss Contributed Surplus")											SFr 8,392				SFr 8,907													$ 7,505	$ 8,036
Dividend or cash distribution approved (in currency per share) | (per share)	SFr 1.27	$ 1.32	SFr 1.04	$ 1.16	SFr 0.96	$ 1.00	SFr 0.80	$ 0.84
Number of quarterly dividend installments | installment	4	4	4	4	4	4	4	4																							4
Cash dividend paid (in dollars per share) | $ / shares											SFr 0.33	$ 0.33	$ 0.29	$ 0.29	SFr 0.29	$ 0.29	$ 0.25	$ 0.25	$ 0.25	$ 0.25	$ 0.21	$ 0.21	$ 0.21	$ 0.21	$ 1.24	$ 1.08	$ 0.92
Cash dividend to be paid in the future (in dollars per share) | $ / shares									$ 0.33	$ 0.33
Common shares, par value (in currency per share) | (per share)							SFr 1.37	$ 1.37			SFr 0.57				SFr 0.57						$ 0.57									$ 0.44	$ 1.28
Unpaid portion of the dividend payment recorded in accrued and other current liabilities | $																												260	$ 236
Number of common shares repurchased																									18	11	20
Amount repurchased | $																									$ 1,163	$ 604	$ 829
Amount available for repurchase, at end of period | $																												2,700
Share repurchase program, authorized amount (in currency) | $																												$ 3,000