Investments Proportional (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 30, 2013		Mar. 31, 2012
Schedule of Equity Method Investments [Line Items]
Equity income in MillerCoors		$ 117.4		$ 118.9
MillerCoors
Schedule of Equity Method Investments [Line Items]
Net income attributable to MillerCoors	271.9	271.9		275.3
MCBC economic interest		42.00%		42.00%
MCBC proportionate share of MillerCoors net income		114.2		115.6
Amortization of the difference between MCBC contributed cost basis and proportional share of the underlying equity in the net assets of MillerCoors		1.2		0.4
Share-based compensation adjustment		2.0	[1]	2.9	[1]
Equity income in MillerCoors		$ 117.4		$ 118.9

[1] The net adjustment is to eliminate all share-based compensation impacts related to pre-existing SABMiller plc equity awards held by former Miller employees now employed by MillerCoors.