Quarterly Financial Data (Tables)

12 Months Ended

Dec. 31, 2017

Quartertly Financial Data [Abstract]

Quarterly financial data

Quarterly financial information for the years ended December 31, 2017 and 2016 are summarized as follows:

(Millions)	2017								2016
Quarters ended		12/31		9/30		6/30		3/31		12/31		9/30		6/30		3/31
Revenues	$	296	$	286	$	253	$	252	$	179	$	180	$	179	$	180
Pretax income		72		85		52		66		20		70		65		57
Net (loss) income (a)	$	(791)	$	72	$	57	$	59	$	29	$	60	$	57	$	51

The fourth quarter of 2017 includes impact of the Tax Act (refer to Note 11).