Related-Party Transactions (Tables)

3 Months Ended

Mar. 31, 2018

Related Party Transactions [Abstract]

Schedule of Related Party Transactions

The amounts of these services follow:

	Three Months Ended March 31,
	2018		2017
(millions)
Affiliated operator service fee(1)	$	69.6	$	75.9
Transportation and storage services from affiliates(1)		20.0		19.6
Services provided by related parties		14.6		10.8
Services provided to related parties		1.4		1.5

(1) The costs of these services were included in purchased gas in Questar Gas' Statements of Income.