Divestitures and Held for Sale - Summary of Long Lived Assets Held-for-sale (Parenthetical) (Detail) $ in Millions	12 Months Ended
Dec. 31, 2020 USD ($)
Property Plant And Equipment Assets Held For Sale Disclosure [Abstract]
Impairment charge to goodwill at business divested prior to current period	$ 4

Goodwill impairment loss at business divested prior to current period.

No definition available.

Name:	apg_GoodwillImpairmentLossAtBusinessDivestedPriorToCurrentPeriod
Namespace Prefix:	apg_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration