Summary of Significant Accounting Policies (Details 4) $ in Millions	3 Months Ended										12 Months Ended
	Dec. 31, 2018 USD ($)		Sep. 30, 2018 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)		Sep. 30, 2017 USD ($)	Jun. 30, 2017 USD ($)	Mar. 31, 2017 USD ($)	Dec. 31, 2018 USD ($) Months Rate		Dec. 31, 2017 USD ($)		Dec. 31, 2016 USD ($)		Jan. 01, 2018 USD ($)	Dec. 31, 2015 USD ($)
Revenues											$ 5,688				$ 6,356
Fiscal period months standard first quarter | Months											2
Period Within Date Of Corresponding Sales In Which Trade Receivables Are Classified As Accounts And Notes Receivable											30 days
Accounts and notes receivable [Abstract]
Accounts and notes receivable, net	$ 561										$ 561
Other Assets	321					$ 375					321		$ 375
Deferred income taxes	195										195
Repurchase Of Shares Of Common Stock [Abstract]
Stock Repurchased During Period, Value											$ (2,394)	[1]	(1,915)	[2]	(5,447)	[2]
Fiscal period months standard second and third quarters | Months											3
Fiscal period months standard fourth quarter | Months											4
Number of periods or months in advance that certain of our international businesses close their books | Months											1
Reduction to Retained earnings
Repurchase Of Shares Of Common Stock [Abstract]
Stock Repurchased During Period, Value											$ (2,356)		(1,915)		(5,399)
Accounting Standards Update 2014-09 [Member]
Accounts and notes receivable [Abstract]
Deferred income taxes																	$ 26
Continuing Operations [Member]
Revenues	1,558		$ 1,391	$ 1,368	$ 1,371	1,577		$ 1,436	$ 1,448	$ 1,417	5,688		5,878		6,356
Receivables [Abstract]
Net amounts included in Other Assets	62					38					62		38
Allowance for doubtful accounts related to notes and direct financing lease receivables	1										1
Accounts and notes receivable [Abstract]
Accounts and notes receivable	592					419					592		419
Allowance for doubtful accounts	(31)					(19)					(31)		(19)
Accounts and notes receivable, net	561					400					561		400
Other Assets	321					375					321		375
Deferred income taxes	195					139					195		139
Other current liabilities	347					343					347		343
Repurchase Of Shares Of Common Stock [Abstract]
Net Cash Provided by (Used in) Operating Activities											1,176		1,030		1,248
Cash, Cash Equivalents and Restricted Cash as presented in the Consolidated Statement of Cash Flows	$ 474	[3]				$ 1,599	[3]				474	[3]	1,599	[3]	831	[3]	$ 1,668	$ 365
Operating Expenses											3,392		3,117		4,674
Franchise and property expenses [Member]
Repurchase Of Shares Of Common Stock [Abstract]
Sales Allowances, Services											11		$ 5		$ 1
2018 [Member] | Accounting Standards Update 2014-09 [Member]
Repurchase Of Shares Of Common Stock [Abstract]
Operating Expenses											$ 1,000
Minimum [Member]
Continuing Fees Rate | Rate											4.00%
Maximum [Member]
Continuing Fees Rate | Rate											6.00%
Capitalized software costs | Minimum [Member]
Finite-Lived Intangible Asset, Useful Life											3 years
Capitalized software costs | Maximum [Member]
Finite-Lived Intangible Asset, Useful Life											7 years

[1] Includes the effect of $5 million in share repurchases (0.1 million shares) with trade dates on, or prior to, December 31, 2018 but settlement dates subsequent to December 31, 2018.

[2] 2017 amount excludes and 2016 amount includes the effect of $45 million in share repurchases (0.7 million shares) with trade dates prior to December 31, 2016 but settlement dates subsequent to December 31, 2016.

[3] Upon adoption of Topic 606 we reclassified cash of $11 million and restricted cash of $58 million, respectively, from Advertising cooperative assets, restricted to Cash and cash equivalents and Prepaid expenses and other current assets. These amounts are included in the Beginning of Period balance of Cash, Cash Equivalents, Restricted Cash and Restricted Cash equivalents in our Consolidated Statement of Cash Flows for the year ended December 31, 2018.