Commitments and Contingencies (Tables)

9 Months Ended

Sep. 30, 2018

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, 2018:

					Long-term Service
	Purchased		Operating		Agreements/Capital		Clause Recoverable
(millions)	Power		Leases		Projects		Commitments		Total
Year ended December 31:
2018	$	7	$	1	$	188	$	105	$	301
2019		0		2		226		229		457
2020		0		2		85		179		266
2021		0		2		32		144		178
2022		0		2		10		136		148
Thereafter		0		36		91		1,122		1,249
Total future minimum payments	$	7	$	45	$	632	$	1,915	$	2,599