Business Combinations - Additional Information (Details) $ / shares in Units, shares in Millions, $ in Millions				3 Months Ended	9 Months Ended
	Sep. 30, 2025 USD ($) $ / shares	Aug. 01, 2025 USD ($) $ / shares shares	Jun. 10, 2025 USD ($) $ / shares	Sep. 30, 2025 USD ($) $ / shares	Sep. 30, 2025 USD ($) Acquisition $ / shares	Jun. 30, 2025 USD ($)	Dec. 31, 2024 USD ($) $ / shares	Sep. 30, 2024 USD ($)	Jun. 30, 2024 USD ($)	Dec. 31, 2023 USD ($)
Business Acquisition [Line Items]
Number of acquisitions | Acquisition					37
Merger consideration shares amount					$ 612
Common stock, par value | $ / shares	$ 0.1			$ 0.1	$ 0.1		$ 0.1
Total revenues related to acquisitions					$ 318
Income before income taxes related to acquisitions					34
Measurement period adjustment, total net assets					5
Measurement period adjustment, goodwill					4
Estimated acquisition earn-out payables	$ 575			$ 575	575	$ 151	$ 167	$ 137	$ 169	$ 249
Maximum future contingency payments acquisitions	353			353	353
Business combination potential earn out payable	431			431	431
Other Noncurrent Liabilities
Business Acquisition [Line Items]
Estimated acquisition earn-out payables	313			313	313
Accounts payable
Business Acquisition [Line Items]
Estimated acquisition earn-out payables	262			262	$ 262
Business Combinations - Stock Deals
Business Acquisition [Line Items]
Number of acquisitions | Acquisition					13
Assets and Assumed Certain Liabilities
Business Acquisition [Line Items]
Number of acquisitions | Acquisition					16
Book of Business Purchases
Business Acquisition [Line Items]
Number of acquisitions | Acquisition					8
RSC Topco, Inc.
Business Acquisition [Line Items]
Aggregate purchase price		$ 9,598
Cash paid		8,293
Merger consideration shares amount		$ 612	$ 1,045
Common stock, par value | $ / shares		$ 0.1	$ 0.1
Maximum potential earn-out amount	0			0	$ 0
RSC Topco, Inc. | Merger Agreement
Business Acquisition [Line Items]
Net consideration held in escrow		$ 750
Cash held in escrow	263	250
Equity held in escrow		500
Merger consideration shares amount		$ 500
Business combination consideration escrowed shares issued | shares		4.5
Share price per share | $ / shares		$ 110.57
Accession acquisition closing price per share | $ / shares		$ 92
Shares held in escrow		$ 406
Change in fair value of shares held in escrow				8
RSC Topco, Inc. | Merger Agreement | Level 3
Business Acquisition [Line Items]
Shares held in escrow	414
Business combination escrow liability amount	$ 676			$ 676	$ 676