Investments (Unrealized Losses and Fair Values) (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Debt Securities, Available-for-sale [Line Items]
Less than 12 months, Fair values	$ 6,838	$ 25,250
Less than 12 months, Unrealized losses	(226)	(191)
12 months or more, Fair values	4,360	2,061
12 months or more, Unrealized losses	(115)	(31)
U.S. Treasury notes [Member]
Debt Securities, Available-for-sale [Line Items]
Less than 12 months, Fair values	1,219	7,728
Less than 12 months, Unrealized losses	(21)	(70)
12 months or more, Fair values	1,444	195
12 months or more, Unrealized losses	(26)	(2)
Other government-related debt securities - U.S. [Member]
Debt Securities, Available-for-sale [Line Items]
Less than 12 months, Fair values	0	188
Less than 12 months, Unrealized losses	0	(1)
12 months or more, Fair values	110	34
12 months or more, Unrealized losses	(2)	(1)
Other government-related debt securities - Foreign and other [Member]
Debt Securities, Available-for-sale [Line Items]
Less than 12 months, Fair values	631	1,163
Less than 12 months, Unrealized losses	(31)	(9)
12 months or more, Fair values	240	115
12 months or more, Unrealized losses	(10)	(2)
Corporate debt securities - Financial [Member]
Debt Securities, Available-for-sale [Line Items]
Less than 12 months, Fair values	1,968	5,928
Less than 12 months, Unrealized losses	(59)	(28)
12 months or more, Fair values	718	462
12 months or more, Unrealized losses	(22)	(6)
Corporate debt securities - Industrial [Member]
Debt Securities, Available-for-sale [Line Items]
Less than 12 months, Fair values	1,898	5,760
Less than 12 months, Unrealized losses	(81)	(43)
12 months or more, Fair values	529	612
12 months or more, Unrealized losses	(18)	(9)
Corporate debt securities - Other [Member]
Debt Securities, Available-for-sale [Line Items]
Less than 12 months, Fair values	529	868
Less than 12 months, Unrealized losses	(20)	(4)
12 months or more, Fair values	28	117
12 months or more, Unrealized losses	(1)	(2)
Residential mortgage-backed securities [Member]
Debt Securities, Available-for-sale [Line Items]
Less than 12 months, Fair values	576	1,838
Less than 12 months, Unrealized losses	(14)	(24)
12 months or more, Fair values	840	276
12 months or more, Unrealized losses	(22)	(6)
Other mortgage- and asset-backed securities [Member]
Debt Securities, Available-for-sale [Line Items]
Less than 12 months, Fair values	17	1,777
Less than 12 months, Unrealized losses	0	(12)
12 months or more, Fair values	451	250
12 months or more, Unrealized losses	$ (14)	$ (3)

Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for more than 12 months.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27337-111563

+ Details

Name:	us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of accumulated unrealized loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for 12 months or longer.

+ References

+ Details

Name:	us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

+ References

+ Details

Name:	us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

+ References

+ Details

Name:	us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss
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_ScheduleOfAvailableForSaleSecuritiesLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_USTreasurySecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_USGovernmentAgenciesDebtSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_ForeignGovernmentDebtSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=amgn_CorporateDebtSecuritiesFinancialMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=amgn_CorporateDebtSecuritiesIndustrialMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=amgn_CorporateDebtSecuritiesOtherMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_ResidentialMortgageBackedSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_AssetBackedSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: