Summary of Significant Accounting Policies (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Advertising Costs
Advertising costs	$ 487	$ 375	$ 373
Minimum
Marketable Investment Securities
The length of time an investment has been in a continuous loss position in which the decline in value would be evaluated on a case by case basis to determine if the decline in value is other-than-temporary	6 months
Length of time an investment has been in a continuous loss position in which the decline in value is considered other-than-temporary	9 months
Inventory
Useful life of rental library product	6 months
Property and Equipment
Useful life of property and equipment	1 year
Business Combinations
Acquired intangible assets, average finite useful life	1 year
Revenue Recognition
Period of deferral for the portion of subscriber fees that are deferred	18 months
Maximum
Marketable Investment Securities
Length of time an investment has been in a continuous loss position in which the decline in value is considered as temporary	6 months
The length of time an investment has been in a continuous loss position in which the decline in value would be evaluated on a case by case basis to determine if the decline in value is other-than-temporary	9 months
Inventory
Useful life of rental library product	24 months
Property and Equipment
Useful life of property and equipment	40 years
Business Combinations
Acquired intangible assets, average finite useful life	10 years
Long-Term Deferred Revenue, Distribution and Carriage Payments
Deferred upfront payment, amortization period	10 years
Revenue Recognition
Period of deferral for the portion of subscriber fees that are deferred	5 years