Discontinued Operations (Details) - USD ($) shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Disposal Group, Including Discontinued Operation, Income Statement Disclosures [Abstract]
Total costs and expenses, discontinued operations	$ 2,639	$ 2,823
Net earnings (loss) from discontinued operations, net of tax (Note 3)	(706)	31
Discontinued Operation, Assets [Abstract]
Total assets, discontinued operations	3,835		$ 4,596
Discontinued Operation, Liabilities [Abstract]
Current portion of long-term debt	23		23
Total long-term debt, net of current portion	$ 8,900		8,902
Discontinued Operations [Member]
Discontinued Operations [Line Items]
Maximum number of Entercom shares to be issued for transaction	105
Change to carrying value of CBS Radio due to fluctuation in Entercom stock price	$ 130
Disposal Group, Including Discontinued Operation, Income Statement Disclosures [Abstract]
Revenues, discontinued operations	250	262
Operating expenses, discontinued operations	89	85
Selling, general and administrative, discontinued operations	122	114
Depreciation and amortization, discontinued operations	0	7
Provision for valuation allowance, discontinued operations	715	0
Total costs and expenses, discontinued operations	926	206
Operating income (loss), discontinued operations	(676)	56
Interest expense, discontinued operations	(19)	0
Earnings (loss) from discontinued operations	(695)	56
Income tax provision, discontinued operations	(11)	(25)
Net earnings (loss) from discontinued operations, net of tax (Note 3)	(706)	$ 31
Discontinued Operation, Assets [Abstract]
Net receivables, discontinued operations	204		244
Other current assets, discontinued operations	54		61
Goodwill, discontinued operations	1,285		1,285
Intangible assets, discontinued operations	2,832		2,832
Net property and equipment, discontinued operations	148		145
Other assets, discontinued operations	27		29
Valuation allowance for carrying value, discontinued operations	(715)		0
Total assets, discontinued operations	3,835		4,596
Discontinued Operation, Liabilities [Abstract]
Current portion of long-term debt	10		10
Other current liabilities, discontinued operations	141		145
Total long-term debt, net of current portion	1,333		1,335
Deferred income tax liabilities, discontinued operations	1,004		998
Other liabilities, discontinued operations	117		118
Total liabilities, discontinued operations	$ 2,605		$ 2,606