Common Stock (Earnings Per Share Data)(Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Common Stock [Line Items]
Income (Loss) from Continuing Operations Attributable to Parent	$ 600	$ 722	$ 1,373	$ 1,468
Average shares, basic	692	707	700	707
Average shares, diluted	692	707	700	707
EPS, basic (usd per share)	$ 0.87	$ 1.02	$ 1.96	$ 2.07
EPS, diluted (usd per share)	$ 0.87	$ 1.02	$ 1.96	$ 2.07
Common Class A [Member]
Common Stock [Line Items]
Income (Loss) from Continuing Operations Attributable to Parent	$ 600	$ 720	$ 1,372	$ 1,464
Average shares, basic	692	707	700	707
Average shares, diluted	692	707	700	707
EPS, basic (usd per share)	$ 0.87	$ 1.02	$ 1.96	$ 2.07
EPS, diluted (usd per share)	$ 0.87	$ 1.02	$ 1.96	$ 2.07
Number of stock options and performance and unvested stock awards excluded from the dilutive securities calculation	2	2	2	2
Dividends declared per share (usd per share)	$ 0.795	$ 0.78	$ 1.59	$ 1.56