Intangible Assets

3 Months Ended

Mar. 31, 2020

Goodwill And Intangible Assets Disclosure [Abstract]

Intangible Assets

7.   Intangible Assets

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

	(Stated in millions)
	Mar. 31, 2020						Dec. 31, 2019
	Gross		Accumulated		Net Book		Gross		Accumulated		Net Book
	Book Value		Amortization		Value		Book Value		Amortization		Value
Customer relationships	$	1,758	$	442	$	1,316	$	3,779	$	868	$	2,911
Technology/technical know-how		1,387		512		875		2,498		779		1,719
Tradenames		772		146		626		1,885		264		1,621
Other		1,553		697		856		1,514		676		838
	$	5,470	$	1,797	$	3,673	$	9,676	$	2,587	$	7,089

Amortization expense charged to income was $133 million during the first quarter of 2020 and $160 million during the first quarter of 2019.

Based on the net book value of intangible assets at March 31, 2020, amortization charged to income for the subsequent five years is estimated to be: remaining three quarters of 2020—$237 million; 2021—$307 million; 2022—$298 million; 2023—$280 million; 2024—$259 million; and 2025—$254 million.