Supplementary Balance Sheet Data (Tables)

9 Months Ended

Sep. 30, 2011

Supplementary Balance Sheet Data [Abstract]

Supplementary Balance Sheet Data

	September 30,		December 31,		September 30,
	2011		2010		2010
Accounts receivable — allowance for doubtful accounts	$	63.7	$	78.0	$	74.1
Accounts receivable — allowance for sales returns		233.2		197.3		241.8
Prepublication costs — accumulated amortization		1,038.4		1,089.3		1,057.8
Property and equipment — accumulated depreciation		1,056.8		1,009.2		997.2