Intangible Assets

A summary of amortizable intangible assets was as follows:



	As of
	April 1, 2016
(Amounts in millions)	Gross Carrying Value		Accumulated Amortization		Net Carrying Value
Outsourcing contract costs	$	828	$	494	$	334
Software	2,243		1,531		712
Customer and other intangible assets	485		203		282
Total intangible assets	$	3,556	$	2,228	$	1,328



	As of
	April 3, 2015
(Amounts in millions)	Gross Carrying Value		Accumulated Amortization		Net Carrying Value
Outsourcing contract costs	$	802	$	476	$	326
Software	2,286		1,568		718
Customer and other intangible assets	292		177		115
Total intangible assets	$	3,380	$	2,221	$	1,159

Amortization expense for the years ended April 1, 2016, April 3, 2015, and March 28, 2014 was $286 million, $374 million, and $364 million, respectively, including amortization of outsourcing contract cost premiums recorded as reductions of revenue of $11 million, $27 million, and $34 million, respectively.

Estimated amortization related to intangible assets, including amortization of contract cost premiums, as of April 1, 2016, for fiscal 2017 through fiscal 2021, is as follows: $283 million, $236 million, $210 million, $185 million, and $139 million, respectively.

During fiscal 2016, CSC sold certain intangible assets to a third party for total cash consideration of $31 million. As a result, CSC recorded a gain on sale of $31 million as a reduction of cost of services in its GIS segment.

During fiscal 2015, CSC sold certain intangible assets to a third party for total consideration of $53 million of which cash consideration was received of $31 million. As a result, CSC recorded a gain on sale of $53 million as a reduction of cost of services in its GIS segment. As of April 1, 2016, CSC had $7 million of outstanding receivables related to these sales, which will be paid in quarterly installments.

Purchased and internally developed software, net of accumulated amortization, consisted of the following:



(Amounts in millions)	April 1, 2016		April 3, 2015
Purchased software	$	206	$	225
Internally developed commercial software	352		363
Internally developed internal-use software	154		130
Total	$	712	$	718

Amortization expense related to purchased software was $99 million, $129 million, and $115 million, for the years ended April 1, 2016, April 3, 2015, and March 28, 2014, respectively. Amortization expense related to internally developed commercial software was $56 million, $61 million, and $54 million, for the years ended April 1, 2016, April 3, 2015, and March 28, 2014, respectively. Amortization expense related to internally developed internal-use software was $9 million, $6 million, and $2 million, for the years ended April 1, 2016, April 3, 2015, and March 28, 2014, respectively.