Goodwill And Other Intangibles (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Segment Reporting Information [Line Items]
Goodwill acquired	$ 626	$ 551
Goodwill expected to be tax deductible	359
Goodwill	9,599	9,089	$ 8,369
Finite lived assets amortization expense	183	$ 169	$ 130
Risk and Insurance Services Segment
Segment Reporting Information [Line Items]
Goodwill acquired	402
Goodwill	6,800
Consulting Segment
Segment Reporting Information [Line Items]
Goodwill acquired	224
Goodwill	$ 2,800

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.

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- Definition

The amount of goodwill arising from a business combination that is expected to be deductible for tax purposes.

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Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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Amount of increase in asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized resulting from a business combination.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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