Investments in Equity Securities (Investment in ABI Narrative) (Details) - USD ($) shares in Millions	1 Months Ended	12 Months Ended
Dec. 31, 2020	Dec. 31, 2020	Dec. 31, 2019
Investments [Line Items]
Equity method investment, difference between carrying amount and fair value, percentage		8.00%	20.00%
ABI [Member]
Investments [Line Items]
Equity method investment, ownership percentage (approximately)	10.00%	10.00%	10.10%
Equity method investment, number of shares owned, restricted (in shares)	185	185
Equity method investment, number of shares owned, common (in shares)	12	12
Restricted shares, lock-up period		5 years
Difference between carrying amount and underlying equity	$ 11,300,000,000	$ 11,300,000,000
Equity method investments	16,651,000,000	$ 16,651,000,000	$ 18,071,000,000
Equity method investment, difference between carrying amount and fair value, percentage		17.00%	11.00%
Proceeds from noncontrolling interests	3,000,000,000
Equity method investment, impairment		$ 0	$ 0
Level 1 [Member] \| ABI [Member]
Investments [Line Items]
Fair value of investment	$ 13,800,000,000	$ 13,800,000,000	$ 16,100,000,000

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

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Equity Method Investment, Impairment

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Equity Method Investment, Number of Shares Owned, Common

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Equity Method Investment, Number of Shares Owned, Restricted

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[Line Items] for Investments [Table]

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Restricted Shares, Lock-up Period

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Difference between amount at which an investment accounted for under the equity method of accounting is carried (reported) on the balance sheet and amount of underlying equity in net assets the reporting Entity has in the investee.

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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 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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Fair value portion of investments accounted under the equity method.

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Amount of cash inflow from a noncontrolling interest. Includes, but is not limited to, purchase of additional shares or other increase in noncontrolling interest ownership.

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