Intangible Assets

3 Months Ended

Mar. 31, 2016

Goodwill And Intangible Assets Disclosure [Abstract]

8. Intangible Assets

The gross book value, accumulated amortization and net book value of intangible assets were as follows:

	(Stated in millions)

	Mar. 31, 2016						Dec. 31, 2015
	Gross		Accumulated		Net Book		Gross		Accumulated		Net Book
	Book Value		Amortization		Value		Book Value		Amortization		Value
Customer Relationships	$	2,503	$	686	$	1,817	$	2,489	$	645	$	1,844
Technology/Technical Know-How		1,866		681		1,185		1,864		653		1,211
Tradenames		1,623		380		1,243		1,625		367		1,258
Other		557		251		306		513		257		256
	$	6,549	$	1,998	$	4,551	$	6,491	$	1,922	$	4,569

Amortization expense charged to income was $89 million during the first quarter of 2016 and $88 million during the first quarter of 2015

Based on the net book value of intangible assets at March 31, 2016, amortization charged to income for the subsequent five years is estimated to be: remaining three quarters of 2016—$287 million; 2017—$372 million; 2018—$364 million; 2019—$351 million; 2020—$330 million; and 2021—$307 million.