Document and Entity Address - USD ($) $ in Billions	12 Months Ended
	Dec. 31, 2019	Jan. 31, 2020	Jun. 30, 2019
Entity Addresses [Line Items]
Entity Address, Address Line One	16600 Swingley Ridge Road
Entity Address, City or Town	Chesterfield
Entity Address, State or Province	MO
Entity Address, Postal Zip Code	63017
City Area Code	636
Local Phone Number	736-7000
Entity Public Float			$ 9.8
Entity Common Stock, Shares Outstanding		62,583,958