Business Combination, Contingent Consideration Arrangements, Revenue Target Period

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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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- Definition

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

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Amount of increase (decrease) in the value of right to a contingent consideration asset.

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- Definition

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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- Definition

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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- Definition

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

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- Definition

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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- Definition

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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- Definition

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

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- Definition

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

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- Definition

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
	Apr. 30, 2019 USD ($)	Mar. 31, 2019 USD ($)	Mar. 31, 2020 USD ($) $ / shares shares	Mar. 31, 2019 USD ($)	Mar. 31, 2020 R / shares	Dec. 31, 2019 USD ($)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Net charge for adjustments related to acquisition related accounts			$ 1	$ 11
Increase in fair value of contingent consideration due to 5% increase in projections			13
Decrease in fair value of contingent consideration due to 5% decrease in projections			17
Carrying value of investment			371			$ 434
Equity securities			18			19
Gain (loss) on equity securities			(1)	3
Equity investments without readily determinable market value			$ 32			67
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			$ 170			183
Private Equity Funds
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Carrying value of investment			97			$ 107
Equity method income			(1)	2
Alexander Forbes Group Holdings Limited
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Share price (per share amount) \| R / shares					R 4.28
Carrying value of investment			$ 105
Shares owned in investment (in shares) \| shares			394
Equity method investment, quoted market value			$ 94
Benefitfocus
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Proceeds from sale of other investments	$ 17	$ 132		$ 115
Unobservable Inputs (Level 3) \| Fair Value, Measurements, Recurring
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Change in contingent purchase consideration			$ 1
Money Market Funds
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Share price (per share amount) \| $ / shares			$ 1.00