Equity (Narrative) (Details) $ in Billions	12 Months Ended
	Dec. 31, 2019 USD ($) vote	Jan. 01, 2017 USD ($)
Equity [Line Items]
Number of votes entitled of each class B common stock | vote	15
New Authorization [Member]
Equity [Line Items]
Stock repurchase program, authorized amount		$ 12.0
Remaining authorized repurchase amount	$ 2.0
Class A Common Stock [Member]
Equity [Line Items]
Voting power	66.67%
Class B Common Stock [Member]
Equity [Line Items]
Voting power	33.33%