Investments in Equity Securities (Investment in ABI Narrative) (Details) - ABI [Member] - USD ($) shares in Millions	9 Months Ended	12 Months Ended
Sep. 30, 2020	Dec. 31, 2019	Mar. 31, 2020
Schedule of Equity Method Investments [Line Items]
Equity method investment, ownership percentage	10.00%		10.10%
Number of restricted shares owned (in shares)	185
Number of ordinary shares owned (in shares)	12
Investments in equity securities	$ 16,716,000,000	$ 18,071,000,000
Difference between carrying amount and fair value, percentage (approximately)	36.00%	11.00%
Equity method investment, impairment	$ 0	$ 0
Fair Value, Inputs, Level 1 [Member]
Schedule of Equity Method Investments [Line Items]
Fair value of equity investment	$ 10,700,000,000	$ 16,100,000,000

Equity Method Investment, Difference Between Carrying Amount and Fair Value, Percentage

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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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Fair value portion of investments accounted under the equity method.

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