Debt (Details) (USD $)	6 Months Ended					12 Months Ended	1 Months Ended
	Dec. 31, 2011	Jul. 02, 2011	Jan. 01, 2011	Dec. 31, 2011 US Uncommitted Lines of Credit [Member]	Dec. 31, 2011 Commercial Paper [Member]	Jul. 02, 2011 Short-term demand loan facility [Member]	Dec. 31, 2011 Commercial Paper Revolver [Member]
Line of credit facility, maximum borrowing capacity				$ 95,000,000			$ 1,000,000,000
Line of credit facility, outstanding borrowings				2,500,000
Short-term bank borrowings	2,500,000	181,975,000	0			182,000,000
Maturity date of short-term bank borrowings						Jul. 04, 2011
Interest rate on short-term bank borrowings						2.00%
Committed facility for unsecured borrowings, expiration date							2016-12-29
Outstanding commercial paper borrowings					375,000,000
Short term bank borrowings and commercial paper borrowings, minimum amount during period	0
Short term bank borrowings and commercial paper borrowings, maximum amount during period	$ 481,400,000