Investments in Equity Securities (Investment in ABI Narrative) (Details) - ABI [Member] - USD ($) shares in Millions	3 Months Ended	12 Months Ended
Mar. 31, 2021	Dec. 31, 2020
Schedule of Equity Method Investments [Line Items]
Equity method investment, ownership percentage	10.00%
Number of restricted shares owned (in shares)	185
Number of ordinary shares owned (in shares)	12
Restricted shares, lock-up period	5 years
Investments in equity securities	$ 17,390,000,000	$ 16,651,000,000
Difference between carrying amount and fair value, percentage (approximately)	28.00%	17.00%
Equity method investment, impairment	$ 0	$ 0
Fair Value, Inputs, Level 1 [Member]
Schedule of Equity Method Investments [Line Items]
Fair value of equity investment	$ 12,400,000,000	$ 13,800,000,000

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

No definition available.

Name:	mo_EquityMethodInvestmentDifferenceBetweenCarryingAmountandFairValuePercentage
Namespace Prefix:	mo_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Equity Method Investment, Impairment

+ References

No definition available.

+ Details

Name:	mo_EquityMethodInvestmentImpairment
Namespace Prefix:	mo_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Equity Method Investment, Number of Shares Owned, Common

+ References

No definition available.

+ Details

Name:	mo_EquityMethodInvestmentNumberofSharesOwnedCommon
Namespace Prefix:	mo_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

Equity Method Investment, Number of Shares Owned, Restricted

+ References

No definition available.

+ Details

Name:	mo_EquityMethodInvestmentNumberofSharesOwnedRestricted
Namespace Prefix:	mo_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

Restricted Shares, Lock-up Period

+ References

No definition available.

+ Details

Name:	mo_RestrictedSharesLockupPeriod
Namespace Prefix:	mo_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

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

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=114001798&loc=d3e33918-111571

+ Details

Name:	us-gaap_EquityMethodInvestmentOwnershipPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

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.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 10
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=109237563&loc=d3e33749-111570

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 25
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e8813-108599

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.12)
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

Name:	us-gaap_EquityMethodInvestments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Fair value portion of investments accounted under the equity method.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 10
-Section 25
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=117311354&loc=d3e32014-111567

+ Details

Name:	us-gaap_EquityMethodInvestmentsFairValueDisclosure
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- 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.

+ References

No definition available.

+ Details

Name:	us-gaap_ScheduleOfEquityMethodInvestmentsLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=mo_ABInBevMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel1Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: