Goodwill and Other Intangibles

The Company is required to assess goodwill and any indefinite-lived intangible assets for impairment annually, or more frequently if circumstances indicate impairment may have occurred. The Company performs the annual impairment assessment for each of its reporting units during the third quarter of each year. In accordance with applicable accounting guidance, the Company assesses qualitative factors to determine whether it is necessary to perform the two-step goodwill impairment test. As part of its assessment, the Company considers numerous factors, including that the fair value of each reporting unit exceeds its carrying value by a substantial margin based on its most recent estimates, whether significant acquisitions or dispositions occurred which might alter the fair value of its reporting units, macroeconomic conditions and their potential impact on reporting unit fair values, actual performance compared with budget and prior projections used in its estimation of reporting unit fair values, industry and market conditions, and the year-over-year change in the Company’s share price. The Company completed its qualitative assessment in the third quarter of 2017 and concluded that a two-step goodwill impairment test was not required in 2017 and that goodwill was not impaired.

Changes in the carrying amount of goodwill are as follows:



June 30,
(In millions)	2018			2017
Balance as of January 1,	$	9,089		$	8,369
Goodwill acquired	116			370
Other adjustments^(a)	(28		)	82
Balance at June 30,	$	9,177		$	8,821

^(a) Primarily reflects the impact of foreign exchange.

Goodwill allocable to the Company’s reportable segments at June 30, 2018 is as follows: Risk and Insurance Services, $6.5 billion and Consulting, $2.7 billion.

Other intangible assets that are not deemed to have an indefinite life are amortized over their estimated lives and reviewed for impairment upon the occurrence of certain triggering events in accordance with applicable accounting literature.

The gross cost and accumulated amortization at June 30, 2018 and December 31, 2017 are as follows:



	June 30, 2018						December 31, 2017
(In millions)	Gross Cost		Accumulated Amortization		Net Carrying Amount		Gross Cost		Accumulated Amortization		Net Carrying Amount
Client Relationships	$	1,711	$	580	$	1,131	$	1,672	$	518	$	1,154
Other ^(a)	237		134		103		234		114		120
Amortized intangibles	$	1,948	$	714	$	1,234	$	1,906	$	632	$	1,274

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

Aggregate amortization expense for the six months ended June 30, 2018 and 2017 was $88 million and $80 million, respectively. The estimated future aggregate amortization expense is as follows:



For the Years Ending December 31,
(In millions)	Estimated Expense
2018 (excludes amortization through June 30, 2018)	$	94
2019	173
2020	154
2021	143
2022	132
Subsequent years	538
	$	1,234