Common Stock (Earnings Per Share Data)(Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Common Stock [Line Items]
Income (Loss) from Continuing Operations Attributable to Parent	$ 937	$ 888	$ 2,310	$ 2,356
Average shares, basic	688	707	696	707
Average shares, diluted	688	707	696	707
EPS, basic (usd per share)	$ 1.36	$ 1.25	$ 3.31	$ 3.33
EPS, diluted (usd per share)	$ 1.36	$ 1.25	$ 3.31	$ 3.33
Common Class A [Member]
Common Stock [Line Items]
Income (Loss) from Continuing Operations Attributable to Parent	$ 935	$ 887	$ 2,307	$ 2,351
Average shares, basic	688	707	696	707
Average shares, diluted	688	707	696	707
EPS, basic (usd per share)	$ 1.36	$ 1.25	$ 3.31	$ 3.33
EPS, diluted (usd per share)	1.36	1.25	$ 3.31	$ 3.33
Number of stock options and performance and unvested stock awards excluded from the dilutive securities calculation			2	2
Dividends declared per share (usd per share)	$ 0.825	$ 0.795	$ 2.42	$ 2.355