Shareholders' Equity (Narrative) (Details) - USD ($) $ / shares in Units, $ in Millions	1 Months Ended	3 Months Ended		6 Months Ended			12 Months Ended
	Jul. 31, 2016	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Dec. 31, 2016	Jun. 30, 2016	Dec. 31, 2016	Jan. 15, 2014
Preferred Stock, Par or Stated Value Per Share		$ 100		$ 100	$ 100		$ 100
Treasury Stock, Shares, Acquired							197,100,000
Treasury Stock, Value, Acquired, Cost Method							$ 4,200.0
Payments for Repurchase of Common Stock				$ 1,045.0		$ 1,515.0
Gain on Realignment of Equity Investment [Member]
Foreign Currency Transaction Gain, before Tax			$ 45.0
Cumulative Unamortized Actuarial Loss Released During Period, Net of Tax			260.0
Cumulative Unamortized Actuarial Loss Released During Period,Tax			19.0
Selling, General and Administrative Expenses [Member]
Foreign Currency Transaction Loss, before Tax			$ 22.0
The 2015 Repurchase Program [Member] | Open Market [Member]
Treasury Stock, Shares, Acquired							110,400,000
Treasury Stock, Value, Acquired, Cost Method							$ 2,200.0
The 2016 ASR Agreement [Member]
Treasury Stock, Shares, Acquired					86,700,000
Payments for Repurchase of Common Stock	$ 2,000.0
The 2016 Repurchase Program [Member]
Stock Repurchase Program, Authorized Amount					$ 4,000.0		$ 4,000.0
The 2015 and 2016 Repurchase Program [Member] | Open Market [Member]
Treasury Stock, Shares, Acquired		5,100,000		20,400,000
Treasury Stock, Value, Acquired, Cost Method		$ 138.1		$ 546.4
The 2017 ASR Agreement [Member]
Treasury Stock, Shares, Acquired		17,100,000
Payments for Repurchase of Common Stock		$ 500.0
Common Stock [Member]
Convertible Preferred Stock, Shares Issued upon Conversion								50,000
Accumulated Net Investment Gain (Loss) Attributable to Parent [Member]
Other Comprehensive Income (Loss), Tax		$ (13.0)		$ (16.0)
Series A Convertible Preferred Stock [Member] | Samsung Corning Precision Materials Co., Ltd. [Member]
Convertible Preferred Stock, Shares Issued upon Conversion		2,300		2,300