Shareholders' Equity - Schedule of Shares Repurchase Plans (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Mar. 31, 2017	Jun. 30, 2017	Jun. 30, 2016
2017 Program
Equity, Class of Treasury Stock [Line Items]
Amount of common stock authorized for repurchase	$ 1,400,000,000.0		$ 1,400,000,000.0
Shares Purchased	0
2016 Program
Equity, Class of Treasury Stock [Line Items]
Amount of common stock authorized for repurchase				$ 1,400,000,000.0
Shares Purchased	2,700,000		9,400,000
Average Cost per Share (USD per share)	$ 83.84		$ 79.93
Total Purchased	$ 227,000,000		$ 750,000,000
Boston Financial Data Services, Inc. and International Financial Data Services
Equity, Class of Treasury Stock [Line Items]
Common stock received in acquisition		$ 158,000,000