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Goodwill and Other Intangibles (Narrative) (Details) - USD ($) | 3 Months Ended | 6 Months Ended |  |
--- | --- | --- | --- | ---
Jun. 30, 2023 | Jun. 30, 2022 | Jun. 30, 2023 | Jun. 30, 2022 | Dec. 31, 2022 | Dec. 31, 2021
Segment Reporting Information [Line Items] |  |  |  |  |  |
Indefinite-lived intangible assets | $ 0 |  | $ 0 |  | $ 0 |
Goodwill | 16,621,000,000 | $ 15,963,000,000 | 16,621,000,000 | $ 15,963,000,000 | $ 16,251,000,000 | $ 16,317,000,000
Aggregate amortization expense | 87,000,000 | $ 83,000,000 | 172,000,000 | $ 174,000,000 |  |
Risk and Insurance Services |  |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |  |
Goodwill expected to be tax deductible | 2,600,000 |  | 2,600,000 |  |  |
Goodwill | 12,600,000,000 |  | 12,600,000,000 |  |  |
Consulting |  |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |  |
Goodwill expected to be tax deductible | 11,300,000 |  | 11,300,000 |  |  |
Goodwill | $ 4,000,000,000 |  | $ 4,000,000,000 |  |  |

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- Definition The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Section 45 -Paragraph 28 -Subparagraph (b) -SubTopic 10 -Topic 230 -Publisher FASB -URI https://asc.fasb.org//1943274/2147482740/230-10-45-28 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 350 -SubTopic 30 -Section 45 -Paragraph 2 -Publisher FASB -URI https://asc.fasb.org//1943274/2147482686/350-30-45-2 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 350 -SubTopic 30 -Section 50 -Paragraph 2 -Subparagraph (a)(2) -Publisher FASB -URI https://asc.fasb.org//1943274/2147482665/350-30-50-2 + Details
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