Supplementary Balance Sheet Data (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011	Jun. 30, 2011
Supplementary Balance Sheet Data
Accounts receivable - allowance for doubtful accounts	$ 52	$ 55	$ 70
Accounts receivable - allowance for sales returns	120	187	146
Prepublication costs - accumulated amortization	1,120	1,066	955
Property and equipment - accumulated depreciation	$ 1,006	$ 1,066	$ 1,056