Stockholders' Equity Class B Common Stock Equity Issuance (Details) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2016 USD ($) shares
Class of Stock [Line Items]
Stock Issued During Period, Shares, New Issues | shares	29.9
Stock Issued During Period, Value, New Issues | $	$ 2,525.6
Class B common stock, non-voting
Class of Stock [Line Items]
Stock Issued During Period, Shares, New Issues | shares	29.9
Stock Issued During Period, Value, New Issues | $	$ 0.3