Intangible Assets, Net

3 Months Ended

Mar. 31, 2017

Intangible assets, net consist of the following (amounts in millions):



	At March 31, 2017
	Estimated useful lives	Gross carrying amount		Accumulated amortization			Net carrying amount
Acquired definite-lived intangible assets:
Internally-developed franchises	3 - 11 years	$	1,154	$	(654	)	$	500
Developed software	2 - 5 years	601		(185		)	416
Customer base	2 years	617		(343		)	274
Trade names	7 - 10 years	54		(10		)	44
Other	1 - 8 years	18		(12		)	6
Total definite-lived intangible assets		$	2,444	$	(1,204	)	$	1,240

Acquired indefinite-lived intangible assets:
Activision trademark	Indefinite						386
Acquired trade names	Indefinite						47
Total indefinite-lived intangible assets							$	433
Total intangible assets, net							$	1,673



	At December 31, 2016
	Estimated useful lives	Gross carrying amount		Accumulated amortization			Net carrying amount
Acquired definite-lived intangible assets:
Internally-developed franchises	3 - 11 years	$	1,154	$	(583	)	$	571
Developed software	3 - 5 years	595		(145		)	450
Customer base	2 years	617		(266		)	351
Trade names	7 - 10 years	54		(8		)	46
Other	1 - 8 years	18		(11		)	7
Total definite-lived intangible assets		$	2,438	$	(1,013	)	$	1,425

Acquired indefinite-lived intangible assets:
Activision trademark	Indefinite						386
Acquired trade names	Indefinite						47
Total indefinite-lived intangible assets							$	433
Total intangible assets, net							$	1,858

Amortization expense of intangible assets was $190 million and $82 million for the three months ended March 31, 2017 and 2016, respectively.

At March 31, 2017, future amortization of definite-lived intangible assets is estimated as follows (amounts in millions):