Intangible Assets

12 Months Ended

Dec. 31, 2015

Goodwill And Intangible Assets Disclosure [Abstract]

Intangible Assets

9.Intangible Assets

A summary of intangible assets follows:

	(Stated in millions)
	2015						2014
	Gross		Accumulated		Net Book		Gross		Accumulated		NetBook
	BookValue		Amortization		Value		BookValue		Amortization		Value
Customer Relationships	$	2,489	$	645	$	1,844		2,531		523	$	2,008
Technology/Technical Know-How		1,864		653		1,211		1,747		535		1,212
Tradenames		1,625		367		1,258		1,641		319		1,322
Other......................		513		257		256		380		268		112
	$	6,491	$	1,922	$	4,569	$	6,299	$	1,645	$	4,654

Customer relationships are generally amortized over periods ranging from 18 to 28 years, technology\technical know-how are generally amortized over periods ranging from 10 to 18 years, and tradenames are generally amortized over periods ranging from 15 to 30 years.

Amortization expense was $354 million in 2015, $344 million in 2014 and $330 million in 2013.

Based on the carrying value of intangible assets at December 31, 2015, amortization expense for the subsequent five years is estimated to be as follows: 2016: $373 million, 2017: $365 million, 2018: $357 million, 2019: $341 million and 2020: $319 million.