CONSOLIDATED CONDENSED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Statement of Comprehensive Income [Abstract]
Net income		$ 61	$ 22	$ 139	$ 105
Other comprehensive (loss) income, net of taxes:
Translation adjustment	[1]	(1)	1	1	(2)
Other comprehensive (loss) income		(1)	1	1	(2)
Comprehensive income		60	23	140	103
Less: comprehensive loss attributable to noncontrolling interests		0	0	(3)	(32)
Comprehensive income attributable to MIC		$ 60	$ 23	$ 143	$ 135

[1] Translation adjustment is presented net of tax expense of $1 million and tax benefit of $1 million for the nine months ended September 30, 2019 and 2018, respectively.