Deferred Revenue (Tables)

12 Months Ended

Dec. 31, 2018

Contract with Customer, Liability [Abstract]

Schedule of Deferred Revenue

As of December 31, 2018, we estimate that our deferred revenue will be recognized in the following years (in millions):

	Original Listing Revenues		Other Listing Revenues		Data Services and Other Revenues		Total
2019	$	19	$	29	$	87	$	135
2020	6		29		3		38
2021	—		21		2		23
2022	—		15		—		15
2023	—		6		—		6
Thereafter	—		—		—		—
Total	$	25	$	100	$	92	$	217

The changes in our deferred revenue during 2018 and 2017 are as follows (in millions), adjusted to reflect the adoption of ASC 606 as discussed in Note 2:

	Annual Listing Revenue			Original Listing Revenues			Other Listing Revenues			Data Services and Other Revenues			Total
Deferred revenue balance at January 1, 2017	$	—		$	23		$	83		$	92		$	198
Additions	368			22			54			374			818
Amortization	(368		)	(20		)	(39		)	(374		)	(801		)
Acquisitions, net of divestitures (Note 3)	—			—			—			1			1
Deferred revenue balance at December 31, 2017	—			25			98			93			216
Additions	384			24			38			366			812
Amortization	(384		)	(24		)	(36		)	(367		)	(811		)
Deferred revenue balance at December 31, 2018	$	—		$	25		$	100		$	92		$	217