Commitments and Contingencies (Tables)

3 Months Ended

Mar. 31, 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 March 31, 2017:

					Long-term Service
	Purchased		Operating		Agreements/Capital		Clause Recoverable
(millions)	Power		Leases		Projects		Commitments		Total
Year ended December 31:
2017	$	11	$	6	$	52	$	515	$	584
2018		10		3		11		264		288
2019		0		2		12		186		200
2020		0		2		7		163		172
2021		0		2		7		132		141
Thereafter		0		38		24		1,157		1,219
Total future minimum payments	$	21	$	53	$	113	$	2,417	$	2,604