Redeemable Noncontrolling Interests - Additional Information (Details) - USD ($) $ in Millions			3 Months Ended	6 Months Ended
	Jun. 22, 2018	Feb. 01, 2017	Jun. 30, 2018	Jun. 30, 2018	Jun. 30, 2017
Business Acquisition [Line Items]
Initial fair value of redeemable noncontrolling interests of acquired businesses			$ 102	$ 102	$ 45
TM4 [Member]
Business Acquisition [Line Items]
Initial fair value of redeemable noncontrolling interests of acquired businesses	$ 102
Ownership percentage by noncontrolling owners	45.00%
BFP and BPT [Member]
Business Acquisition [Line Items]
Initial fair value of redeemable noncontrolling interests of acquired businesses		$ 45
Ownership percentage by noncontrolling owners		20.00%