Shareholders' Equity - Shares Repurchased (Details) - USD ($)	2 Months Ended	12 Months Ended
	Feb. 27, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Equity, Class of Treasury Stock [Line Items]
Total payments		$ 500,000,000	$ 500,000,000	$ 501,000,000
Common Stock [Member]
Equity, Class of Treasury Stock [Line Items]
Number of Shares Repurchased (in shares)		11,163,929	13,243,107	12,669,643
Total payments		$ 500,000,000	$ 500,000,000	$ 501,000,000
Average Price Paid Per Share (in dollars per share)		$ 44.79	$ 37.76	$ 39.57
Subsequent Event [Member] | Common Stock [Member]
Equity, Class of Treasury Stock [Line Items]
Authorized repurchase amount	$ 250,000,000
Remaining number of shares authorized to be repurchased	$ 408,000,000
Number of Shares Repurchased (in shares)	843,729
Total payments	$ 40,000,000
Average Price Paid Per Share (in dollars per share)	$ 47.41