Description of Business and Summary of Significant Accounting Policies Description of Business and Summary of Significant Accounting Policies - Goodwill and Indefinite-Lived Intangible Assets (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Accounting Policies [Abstract]
Goodwill, impairment loss	$ 0	$ 0	$ 0
Reporting unit, amount of fair value in excess of carrying amount	$ 700,000,000