Goodwill and Other Intangibles (Tables)

12 Months Ended

Dec. 31, 2020

Goodwill and Intangible Assets Disclosure [Abstract]

Changes in the carrying amount of goodwill

Changes in the carrying amount of goodwill are as follows: 

(In millions of dollars)	2020		2019
Balance as of January 1, as reported	$	14,671	$	9,599
Goodwill acquired (a)	593		5,124
Other adjustments (b)	253		(52)
Balance at December 31,	$	15,517	$	14,671

(a) Includes $4.9 billion from the acquisition of JLT in 2019.

(b) Primarily reflects the impact of foreign exchange and dispositions.

Schedule of finite-lived intangible assets

The gross cost and accumulated amortization of intangible assets at December 31, 2020 and 2019 are as follows:

(In millions of dollars)	2020						2019
	Gross Cost		Accumulated Amortization		Net Carrying Amount		Gross Cost		Accumulated Amortization		Net Carrying Amount
Customer relationships	$	3,713	$	1,170	$	2,543	$	3,494	$	897	$	2,597
Other (a)	386		230		156		380		203		177
Amortized intangibles	$	4,099	$	1,400	$	2,699	$	3,874	$	1,100	$	2,774

(a) Primarily non-compete agreements, trade names and developed technology.

Estimated future aggregate amortization expense

The estimated future aggregate amortization expense is as follows:

For the Years Ending December 31,
(In millions of dollars)
2021	$	356
2022	327
2023	300
2024	285
2025	275
Subsequent years	1,156
	$	2,699