QUARTERLY FINANCIAL DATA (UNAUDITED) (Tables)

12 Months Ended

Dec. 31, 2018

Quarterly Financial Information Disclosure [Abstract]

Schedule of quarterly financial information

Accordingly, comparisons among quarters of a year may not represent overall trends and changes in operations.

	First Quarter		Second Quarter		Third Quarter		Fourth Quarter
(in millions)	2018
Operating Revenue	$	275	$	354	$	460	$	344
Operating Income	43		83		126		36
Net Income	24		58		95		11
	2017
Operating Revenue	$	268	$	352	$	417	$	304
Operating Income	37		107		138		44
Net Income	21		61		82		13