Shareholders' Equity (Tables)

12 Months Ended

Dec. 31, 2018

Equity [Abstract]

Schedule of Share Repurchases

Share Repurchases

Year	Number of Shares Repurchased	Total Payments (in millions)		Average Price Paid Per Share
2016	10,721,248	$	306	$	28.53
2017	12,669,643	$	501	$	39.57
2018	13,243,107	$	500	$	37.76
2019 (through March 1, 2019 on a settlement date basis)	1,200,501	$	48	$	40.03