Long-Term Debt (Equity Units and RSNs) (Details) - USD ($) shares in Millions			12 Months Ended
	Jan. 01, 2017	Oct. 05, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Oct. 31, 2016
Financial Instruments Subject to Mandatory Redemption by Settlement Terms [Line Items]
Total Net Proceeds		$ 654,000,000	$ 0	$ 654,000,000	$ 0
Total Long-Term Debt			1,420,000,000
Equity units subject to mandatory redemption
Financial Instruments Subject to Mandatory Redemption by Settlement Terms [Line Items]
Units Issued (in shares)		13.5
Stock Purchase Contract Annual Rate	5.00%	5.00%
Stock Purchase Contract Liability(a)		$ 98,000,000	66,000,000	$ 98,000,000
Redemption of long-term debt			$ 32,000,000
October series C 1.5% RSNs maturing 2024 | Other long-term debt
Financial Instruments Subject to Mandatory Redemption by Settlement Terms [Line Items]
Total Long-Term Debt		$ 675,000,000				$ 675,000,000
RSN Annual Interest Rate		1.50%				1.50%