Quarterly Financial Data (Unaudited) (Tables)

12 Months Ended

Dec. 31, 2020

Quarterly Financial Data [Abstract]

Quarterly financial data

Quarterly financial information for the years ended December 31, 2020 and 2019 are summarized as follows:

(Millions)	2020								2019
Quarters ended	12/31		9/30		6/30		3/31		12/31		9/30		6/30		3/31
Revenues	$	139	$	76	$	349	$	266	$	377	$	388	$	418	$	432
Pretax income	120		46		114		42		132		131		130		119
Net income	$	71	$	26	$	82	$	22	$	93	$	110	$	112	$	103