Capital Stock (Narrative) (Details) - USD ($)		12 Months Ended			29 Months Ended
	Aug. 01, 2012	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2014
Capital Stock [Line Items]
Common Stock, Shares Authorized (in shares)		6,000,000,000.0
Common stock repurchased		$ 0	$ 0	$ 3,800,000,000
Shares of common stock reserved (in shares)		27,213,699
Preferred stock shares authorized (in shares)		250,000,000
$18 Billion Dollar Share Repurchase Program 2012 [Member]
Capital Stock [Line Items]
Stock repurchase program, period in force (years)	3 years
Common stock repurchase, amount authorized (in shares)	$ 18,000,000,000
Repurchase of shares (in shares)					144,600,000
Common stock repurchased					$ 12,700,000,000
Acquired average price per share (in dollars per share)					$ 87.48