Commitments and Contingencies (Tables)

9 Months Ended

Sep. 30, 2017

Commitments And Contingencies Disclosure [Abstract]

Schedule of Long-term Commitments

The following is a schedule of future payments under PPAs, minimum lease payments with non-cancelable lease terms in excess of one year, and other net purchase obligations/commitments at September 30, 2017:

					Long-term Service
	Purchased		Operating		Agreements/Capital		Clause Recoverable
(millions)	Power		Leases		Projects		Commitments		Total
Year ended December 31:
2017	$	3	$	1	$	38	$	124	$	166
2018		10		3		173		282		468
2019		0		2		74		187		263
2020		0		2		7		163		172
2021		0		2		7		133		142
Thereafter		0		38		29		1,159		1,226
Total future minimum payments	$	13	$	48	$	328	$	2,048	$	2,437