Note 11 - Stockholders' Equity (Details Textual) - USD ($) $ / shares in Units, $ in Millions					1 Months Ended			3 Months Ended		6 Months Ended
	Apr. 27, 2022	Apr. 01, 2022	Feb. 16, 2022	Jan. 04, 2022	Jun. 30, 2022	May 31, 2022	Feb. 28, 2022	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Mar. 31, 2022	Dec. 31, 2021
Common Stock, Shares Authorized (in shares)					2,000,000,000			2,000,000,000		2,000,000,000			2,000,000,000
Share Price (in dollars per share)					$ 173.09			$ 173.09		$ 173.09			$ 227.90
Preferred Stock, Shares Authorized (in shares)					80,000,000			80,000,000		80,000,000
Preferred Stock, Par or Stated Value Per Share (in dollars per share)					$ 0.001			$ 0.001		$ 0.001
Preferred Stock, Shares Issued (in shares)					0			0		0			0
Common Stock, Dividends, Per Share, Declared (in dollars per share)	$ 0.31		$ 0.31
Payments of Ordinary Dividends, Common Stock								$ 98.6	$ 94.2
Treasury Stock, Shares, Acquired (in shares)								1,561,149	834,012	4,613,710	1,394,538
Treasury Stock, Value, Acquired, Cost Method								$ 325.0	$ 150.0	$ 896.3	$ 250.0
Treasury Stock, Shares, Total (in shares)					385,745,940			385,745,940		385,745,940			382,351,399
Stock Issued During Period, Shares, Treasury Stock Reissued (in shares)										1,219,169
Shares Issued, Price Per Share (in dollars per share)					$ 13.95			$ 13.95		$ 13.95
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount (in shares)								1,369,746	785,547	1,387,713	866,055
Additional ASR Agreement With Citibank, N.A. [Member]
Stock Repurchase Program, Authorized Amount												$ 325.0	$ 100.0
Treasury Stock, Shares, Acquired (in shares)		1,211,387		360,913		349,762	141,766			2,063,828
Treasury Stock Acquired, Average Cost Per Share (in dollars per share)						$ 208.18	$ 198.93
Accelerated Share Repurcahse ("ASR") Agreement with Morgan Stanley [Member]
Stock Repurchase Program, Authorized Amount					$ 300.0			$ 300.0		$ 300.0
Treasury Stock, Shares, Acquired (in shares)					1,386,562					4,613,710
Treasury Stock Acquired, Average Cost Per Share (in dollars per share)					$ 173.09					$ 194.28
Treasury Stock, Value, Acquired, Cost Method					$ 240.0					$ 896.3
Stock Repurchase Program, Remaining Authorized Repurchase Amount					$ 707.5			$ 707.5		$ 707.5
February 16, 2022 Share Repurchase Program [Member]
Stock Repurchase Program, Authorized Amount			$ 1,000.0