Acquisitions and Dispositions (Schedule of Dispositions) (Details) - CNET Media Group [Member] - Disposition, Held-for-sale [Member] $ in Millions	Sep. 30, 2020 USD ($)
Assets
Current assets	$ 39
Property and equipment	6
Goodwill	114
Intangible assets, net	108
Other assets (noncurrent)	4
Total assets	271
Liabilities
Other current liabilities	32
Other liabilities (noncurrent)	4
Total liabilities	$ 36