v3.21.2

Derivative Financial Instruments - Additional Information (Details) $ in Millions	1 Months Ended	9 Months Ended
	Jul. 31, 2021 USD ($) Hedge	Sep. 30, 2021 USD ($)
Derivative [Line Items]
Number of hedges terminated | Hedge	3
Number of previously unfloored hedges amended | Hedge	2
Interest rate floor basis points	0.50%
Derivative losses included in Accumulated other comprehensive loss to be reclassified into earnings over next twelve months | $		$ 2
Term Loan
Derivative [Line Items]
Repayment of principal | $	$ 556

X

- Definition

Number of hedges terminated.

+ References

No definition available.

+ Details

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Namespace Prefix:	alit_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

X

- Definition

Number of previously unfloored hedges amended.

+ References

No definition available.

+ Details

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Namespace Prefix:	alit_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

X

- Definition

The estimated net amount of existing gains or losses on cash flow hedges at the reporting date expected to be reclassified to earnings within the next 12 months.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=121549185&loc=d3e80748-113994

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

X

- Definition

The percentage points added to the reference rate to compute the variable rate on the interest rate derivative.

+ References

No definition available.

+ Details

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

X

- 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

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
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X

- Definition

The cash outflow for debt initially having maturity due after one year or beyond the normal operating cycle, if longer.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 15
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3291-108585

+ Details

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Balance Type:	credit
Period Type:	duration

X

- Details

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