Segment Information (Tables)

6 Months Ended

Jun. 30, 2015

Segment Reporting [Abstract]

Schedule of Segment Reporting Information, by Segment

The following tables provide information on a reportable segment basis (in millions):

	Three-Month Periods				Six-Month Periods
	Ended June 30,				Ended June 30,
	2015		2014		2015		2014
Operating revenue:
Regulated electric	$	201	$	179	$	397	$	356
Regulated gas	26		21		76		65
Total operating revenue	$	227	$	200	$	473	$	421
Cost of sales:
Regulated electric	$	101	$	86	$	198	$	166
Regulated gas	15		12		50		41
Total cost of sales	$	116	$	98	$	248	$	207
Gross margin:
Regulated electric	$	100	$	93	$	199	$	190
Regulated gas	11		9		26		24
Total gross margin	$	111	$	102	$	225	$	214
Operating and maintenance:
Regulated electric	$	35	$	35	$	67	$	64
Regulated gas	4		4		8		9
Total operating and maintenance	$	39	$	39	$	75	$	73
Depreciation and amortization:
Regulated electric	$	24	$	23	$	48	$	45
Regulated gas	4		3		8		7
Total depreciation and amortization	$	28	$	26	$	56	$	52
Operating income:
Regulated electric	$	34	$	29	$	71	$	70
Regulated gas	3		2		9		7
Total operating income	$	37	$	31	$	80	$	77
Interest expense:
Regulated electric	$	14	$	14	$	28	$	28
Regulated gas	1		1		2		2
Total interest expense	$	15	$	15	$	30	$	30

	As of
	June 30,		December 31,
	2015		2014
Total assets:
Regulated electric	$	3,000	$	3,031
Regulated gas	322		327
Regulated common assets(1)	121		30
Total assets	$	3,443	$	3,388

(1) Consists principally of cash and cash equivalents not included in either the regulated electric or regulated natural gas segments.