Investments (Schedule Of Investments In Partially-Owned Insurance Companies) (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Investment [Line Items]
Document Period End Date	Dec. 31, 2020
Carrying Value	$ 2,813	$ 1,332
Goodwill	15,400	15,296	$ 15,271
Equity Method Investment, Difference Between Carrying Amount and Underlying Equity	$ 1,385	527
Huatai Group [Member]
Investment [Line Items]
Ownership Percentage	47.10%
Huatai Group [Member] \| CHINA
Investment [Line Items]
Carrying Value	$ 2,461	$ 1,053
Ownership Percentage	47.00%	31.00%
Equity Method Investment, Difference Between Carrying Amount and Underlying Equity	$ 1,313	$ 460
Huatai Life Insurance Co. [Member] \| CHINA
Investment [Line Items]
Carrying Value	$ 201	$ 147
Ownership Percentage	20.00%	20.00%
Equity Method Investment, Difference Between Carrying Amount and Underlying Equity	$ 69	$ 64
Freisenbruch-Meyer \| Bermuda
Investment [Line Items]
Carrying Value	$ 10	$ 10
Ownership Percentage	40.00%	40.00%
Equity Method Investment, Difference Between Carrying Amount and Underlying Equity	$ 3	$ 3
Chubb Arabia Cooperative Insurance Company [Member] \| Saudi Arabia
Investment [Line Items]
Carrying Value	$ 23	$ 20
Ownership Percentage	30.00%	30.00%
Equity Method Investment, Difference Between Carrying Amount and Underlying Equity	$ 0	$ 0
Russian Reinsurance Company \| Russia
Investment [Line Items]
Carrying Value	$ 4	$ 2
Ownership Percentage	23.00%	23.00%
Equity Method Investment, Difference Between Carrying Amount and Underlying Equity	$ 0	$ 0
ABR Reinsurance Capital Holdings Ltd. [Member] \| Bermuda
Investment [Line Items]
Carrying Value	$ 114	$ 100
Ownership Percentage	15.60%	12.00%
Equity Method Investment, Difference Between Carrying Amount and Underlying Equity	$ 0	$ 0
Direct Ownership [Member] \| Huatai Life Insurance Co. [Member] \| CHINA
Investment [Line Items]
Ownership Percentage	20.00%
Indirect Ownership [Member] \| Huatai Life Insurance Co. [Member] \| CHINA
Investment [Line Items]
Ownership Percentage	37.50%
Total Direct and Indirect [Member] \| Huatai Life Insurance Co. [Member] \| CHINA
Investment [Line Items]
Ownership Percentage	57.50%

This table lists the investments. The line items identify information about all investments.

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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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