Intangible Assets

3 Months Ended

Mar. 31, 2019

Goodwill And Intangible Assets Disclosure [Abstract]

Intangible Assets

6.   Intangible Assets

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

	(Stated in millions)
	Mar. 31, 2019						Dec. 31, 2018
	Gross		Accumulated		Net Book		Gross		Accumulated		Net Book
	BookValue		Amortization		Value		Book Value		Amortization		Value
Customer relationships	$	4,772	$	1,302	$	3,470	$	4,768	$	1,243	$	3,525
Technology/technical know-how		3,463		1,275		2,188		3,494		1,246		2,248
Tradenames		2,799		653		2,146		2,799		628		2,171
Other		1,428		621		807		1,404		621		783
	$	12,462	$	3,851	$	8,611	$	12,465	$	3,738	$	8,727

Amortization expense charged to income was $160 million during the first quarter of 2019 and $165 million during the first quarter of 2018.

Based on the net book value of intangible assets at March 31, 2019, amortization charged to income for the subsequent five years is estimated to be: remaining three quarters of 2019—$510 million; 2020—$657 million; 2021—$628 million; 2022—$622 million; 2023—$609 million; and 2024—$563 million.