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Business Combination, Contingent Consideration, Asset, Fair Value Disclosure

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Decrease in Fair Value of Contingent Consideration Due to 5% Decrease in Projections

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Equity Method Investment, Shares Owned

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Increase in Fair Value of Contingent Consideration Due to 5% Increase in Projections

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- Definition

Carrying amount as of the balance sheet date of the asset arising from derivative instruments and hedging activities, which are expected to be converted into cash or otherwise disposed of within a year or the normal operating cycle, if longer.

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This item represents an other than temporary decline in value that has been recognized against an investment accounted for under the equity method of accounting. The excess of the carrying amount over the fair value of the investment represents the amount of the write down which is or was reflected in earnings. The written down value is a new cost basis with the adjusted value of the investment becoming its new carrying value subject to the equity accounting method. Evidence of a loss in value might include, but would not necessarily be limited to, absence of an ability to recover the carrying amount of the investment or inability of the investee to sustain an earnings capacity which would justify the carrying amount of the investment.

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The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

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This item represents the aggregate value of each identified investment accounted for under the equity method of accounting based on the quoted market price for those investments in common stock for which a quoted market price is available.

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This item represents the carrying amount on the entity's balance sheet of its investment in common stock of an equity method investee. This is not an indicator of the fair value of the investment, rather it is the initial cost adjusted for the entity's share of earnings and losses of the investee, adjusted for any distributions (dividends) and other than temporary impairment (OTTI) losses recognized.

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Amount of investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).

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Amount of realized gain (loss) from sale of investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).

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Amount of investment in equity security without readily determinable fair value.

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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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Amount of gain (loss) recognized in income from liability measured at fair value on recurring basis using unobservable input (level 3).

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Amount of income (loss) for proportionate share of equity method investee's income (loss).

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Amount of cash inflow from the sale of investments classified as other.

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Price of a single share of a number of saleable stocks of a company.

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No definition available.

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Fair Value Measurements (Narrative) (Details) $ / shares in Units, shares in Millions, $ in Millions	1 Months Ended		3 Months Ended				9 Months Ended
	Apr. 30, 2019 USD ($)	Mar. 31, 2019 USD ($)	Sep. 30, 2019 USD ($) $ / shares shares	Jun. 30, 2019 USD ($)	Mar. 31, 2019 USD ($)	Sep. 30, 2018 USD ($)	Sep. 30, 2019 USD ($) $ / shares shares	Sep. 30, 2018 USD ($)	Sep. 30, 2019 R / shares	Dec. 31, 2018 USD ($)	Sep. 30, 2018 R / shares	Dec. 31, 2014 R / shares
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Net charge for adjustments related to acquisition related accounts							$ 26	$ 19
Increase in fair value of contingent consideration due to 5% increase in projections							46
Decrease in fair value of contingent consideration due to 5% decrease in projections							39
Carrying value of investment			$ 452				452			$ 287
Equity method income			3			$ 4	10	14
Equity securities			19				19			146
Gains on equity securities			4			25	10	43
Equity investments without readily determinable market value			47				$ 47			75
Minimum
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Revenue target period (in years)							2 years
Maximum
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Revenue target period (in years)							4 years
Private Insurance and Consulting
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Carrying value of investment			219				$ 219			61
Private Equity Funds, Non-US
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Carrying value of investment			95				95			82
Alexander Forbes Group Holdings Limited
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Share price (per share amount) \| R / shares									R 5.6		R 4.95	R 7.50
Carrying value of investment			$ 138				$ 138
Percentage of ownership in equity investment			33.00%				33.00%
Other than temporary impairment						$ 81		$ 81
Shares owned in investment (in shares) \| shares			443				443
Equity method investment, quoted market value			$ 166				$ 166
Benefitfocus
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Proceeds from sale of other investments	$ 17	$ 132			$ 115
Payscale
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Proceeds from sale of other investments				$ 47
Treasury Lock \| Jardine Lloyd Thompson Group plc
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative hedges, assets										2,000
Money Market Funds
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Share price (per share amount) \| $ / shares			$ 1.00				$ 1.00
Fair Value, Measurements, Recurring \| Other Assets
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Contingent purchase consideration asset			$ 65				$ 65			0
Equity securities			5				5			133
Fair Value, Measurements, Recurring \| Other Assets \| Unobservable Inputs (Level 3)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Contingent purchase consideration asset			65				65			0
Equity securities			$ 0				$ 0			$ 0