Shareholder's equity (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	12 Months Ended
	Feb. 10, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 10, 2020	Nov. 04, 2019
Stock repurchases
Repurchase of common stock (in shares)		16,477,000	41,020,000	16,844,000
Value of treasury stock acquired		$ 1,446,767	$ 2,402,475	$ 1,153,511
Treasury stock acquired, average cost per share		$ 87.80	$ 58.57	$ 68.48
Stock Repurchase Program, Authorized Amount					$ 2,000,000	$ 2,000,000
Terminated Remaining Prior Share Repurchases Authorized, Amount					$ 329,302	$ 246,373
Charter documents and Delaware law:
Preferred stock, shares authorized (in shares)		5,000,000	5,000,000
Period During Which The Company Is Subject To Section 203 Of The Delaware General Corporation Law Limitation		3 years
Payments to Noncontrolling Interests		$ 7,831	$ 68,019	$ 28,082
Treasury stock
Stock repurchases
Repurchase of common stock (in shares)		16,477,000	41,020,000	16,844,000
Value of treasury stock acquired		$ 1,446,767	$ 2,402,475	$ 1,153,511
Retirement of treasury stock (in shares)		16,477,000	41,020,000	16,844,000
Subsequent Event
Stock repurchases
Repurchase of common stock (in shares)	1,063,000
Value of treasury stock acquired	$ 123,282
Treasury stock acquired, average cost per share	$ 115.98
Stock Repurchase Program, Remaining Authorized Repurchase Amount	$ 1,806,674