Shareholders' Equity Narrative (Details) - USD ($) $ / shares in Units, $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Shareholders' Equity [Abstract]
Preferred Stock, No Par Value	$ 0
Common Stock, Shares Authorized	1,000,000,000
Preferred Stock, Shares Authorized	500,000
Common Stock, No Par Value	$ 0
Preferred Stock, Shares Issued	0
Treasury Stock, Shares	158,700,000	143,200,000
Treasury Stock, Value	$ 5,500	$ 5,500
Derivatives used in Net Investment Hedge, Net of Tax	$ 59	$ (40)