Note 8. Supplemental Balance Sheet Information Other Assets, Noncurrent (Details) - USD ($) $ in Millions		Dec. 31, 2018	Jan. 01, 2018	Dec. 31, 2017
Other Assets, Noncurrent [Line Items]
Other assets		$ 724
Continuing Operations [Member]
Other Assets, Noncurrent [Line Items]
Other assets		724		$ 345
Other Assets, Miscellaneous, Noncurrent		369		345
GrubHub Inc. [Domain] | Fair Value, Inputs, Level 1 [Member] | Other Assets [Member] | Fair Value, Measurements, Recurring [Member] | Continuing Operations [Member]
Other Assets, Noncurrent [Line Items]
Equity Securities, FV-NI	[1]	214
GrubHub Inc. [Member] | Fair Value, Inputs, Level 1 [Member] | Other Assets [Member] | Fair Value, Measurements, Recurring [Member] | Continuing Operations [Member]
Other Assets, Noncurrent [Line Items]
Equity Securities, FV-NI	[1]			0
Franchise Incentive [Member] | Continuing Operations [Member]
Other Assets, Noncurrent [Line Items]
Other assets	[2]	$ 141		$ 0
Franchise Incentive [Member] | Accounting Standards Update 2014-09 [Member]
Other Assets, Noncurrent [Line Items]
Other assets			$ 118

[1] Refer to Note 5 for additional discussion regarding our investment in Grubhub.

[2] Increase from 2017 primarily due to the adoption of Topic 606 beginning with the year ended December 31, 2018. See Note 2.