Acquisitions (Narrative) (Details) $ in Millions, kr in Billions				3 Months Ended	9 Months Ended
		Sep. 06, 2019 USD ($)	Sep. 06, 2019 SEK (kr)	Sep. 30, 2020 USD ($)	Sep. 30, 2020 USD ($) item	Sep. 30, 2019 USD ($) entity	Dec. 31, 2019 USD ($)	Mar. 31, 2018 USD ($)
Acquisitions [Line Items]
Number of Businesses Acquired | entity						27
Net cash paid					$ 29	$ 338
Goodwill				$ 2,127	2,127		$ 2,096
Goodwill in period						224
Capital adjustments clawbacks					3
Contingent consideration, revered amount repaid				1
Acquisition related costs								$ 4
Acquisition-related Costs [Member]
Acquisitions [Line Items]
Pro forma financial information adjustment, quarterly interest expense					$ 1
Trade Names [Member]
Acquisitions [Line Items]
Other intangibles related to acquisitions						35
Other Intangible Assets [Member]
Acquisitions [Line Items]
Other intangibles related to acquisitions						$ 114
Nine Tuck-In Pest Control [Member]
Acquisitions [Line Items]
Number of Businesses Acquired | item					9
Net cash paid					$ 12
Two Pest Control [Member]
Acquisitions [Line Items]
Number of Businesses Acquired | item					2
Net cash paid					$ 18
Business Combinations [Member]
Acquisitions [Line Items]
Number of Businesses Acquired | entity						24
Asset Acquisitions [Member]
Acquisitions [Line Items]
Number of Businesses Acquired | entity						3
Pest Control Acquisition [Member]
Acquisitions [Line Items]
Contingent consideration				3	3
Goodwill				$ 10	$ 10
Nomor [Member]
Acquisitions [Line Items]
Cash Acquired from Acquisition		$ 9
Net cash paid		198	kr 2
Goodwill		153
Proceeds from revolving credit facility		120
Other intangibles related to acquisitions	[1]	$ 66
Minimum [Member] | Pest Control Acquisition [Member]
Acquisitions [Line Items]
Contingent consideration, term					1 year
Maximum [Member] | Pest Control Acquisition [Member]
Acquisitions [Line Items]
Contingent consideration, term					3 years

[1] Primarily customer lists.