

	Power Generation		Gas Infrastructure		Power Delivery		Corporate and Other (1)		Total

(millions)
Dominion Energy
Balance at December 31, 2016 (2)	$	1,422	$	4,051	$	926	$	—	$	6,399
Dominion Energy Questar Combination		—		6 (3)		—		—		6

Balance at December 31, 2017 (2)	$	1,422	$	4,057	$	926	$	—	$	6,405
Purchase Accounting Adjustment		—		5		—		—		5

Balance at December 31, 2018 (2)	$	1,422	$	4,062	$	926	$	—	$	6,410

Dominion Energy Gas
Balance at December 31, 2016 (2)	$	—	$	1,466	$	—	$	—	$	1,466
No events affecting goodwill		—		—		—		—		—

Balance at December 31, 2017 (2)	$	—	$	1,466	$	—	$	—	$	1,466
Purchase Accounting Adjustment		—		5		—		—		5

Balance at December 31, 2018 (2)	$	—	$	1,471	$	—	$	—	$	1,471

(1)	Goodwill recorded at the Corporate and Other segment is allocated to the primary operating segments for goodwill impairment testing purposes.

(2)	Goodwill amounts do not contain any accumulated impairment losses.

(3)	See Note 3.

Other Intangible Assets

The Companies’ other intangible assets are subject to amortization over their estimated useful lives. Dominion Energy’s amortization expense for intangible assets was $82 million, $80 million and $73 million for 2018, 2017 and 2016, respectively. In 2018, Dominion Energy acquired $127 million of intangible assets, primarily representing software and

right-of-use

assets, with an estimated weighted-average amortization period of approximately 15 years. Amortization expense for Virginia Power’s intangible assets was $31 million for both 2018 and 2017 and $29 million for 2016. In 2018, Virginia Power acquired $49 million of intangible assets, primarily representing software, with an estimated weighted-average amortization period of 11 years. Dominion Energy Gas’ amortization expense for intangible assets was $11 million, $9 million and $11 million for 2018, 2017 and 2016, respectively. In 2018, Dominion Energy Gas acquired $35 million of intangible assets, primarily representing a contractual agreement with a local taxing authority, software and

right-of-use

assets, with an estimated weighted-average amortization period of approximately 13 years. The components of intangible assets are as follows:



	2018				2017

At December 31,	Gross Carrying Amount		Accumulated Amortization		Gross Carrying Amount		Accumulated Amortization

(millions)
Dominion Energy
Software, licenses and other	$	1,033	$	363	$	1,043	$	358

Virginia Power
Software, licenses and other	$	384	$	134	$	347	$	114

Dominion Energy Gas
Software, licenses and other	$	179	$	64	$	151	$	60

Annual amortization expense for these intangible assets is estimated to be as follows:



	2019		2020		2021		2022		2023

(millions)
Dominion Energy	$	67	$	56	$	44	$	34	$	23

Virginia Power	$	29	$	23	$	16	$	12	$	6

Dominion Energy Gas	$	10	$	9	$	9	$	7	$	6