Shareholders' Equity Repurchase Activity (Details) $ in Billions	6 Months Ended
	Jun. 30, 2017 USD ($) shares
Class of Stock [Line Items]
Treasury Stock, Shares, Acquired | shares	0
Stock Repurchase Program, Remaining Authorized Repurchase Amount | $	$ 5.7
Treasury Stock Shares Acquired From Inception | shares	201,000,000
Treasury Stock Value Acquired Cost Method From Inception | $	$ 8.4