Merger With VLP (Details) - USD ($) $ / shares in Units, $ in Millions		3 Months Ended
	Jan. 10, 2019	Mar. 31, 2019	Mar. 31, 2018
Merger with VLP (Textual)
Merger transaction, aggregate merger consideration funded with available cash on hand		$ 950	$ 0
VLP [Member]
Merger with VLP (Textual)
Merger transaction, price per common unit (in usd per unit)	$ 42.25
Merger transaction, aggregate merger consideration funded with available cash on hand	$ 950