Common Stock (Earnings Per Share Data)(Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Income (Loss) from Continuing Operations Attributable to Parent									$ 2,796	$ 2,451	$ 2,574
Weighted Average Number of Shares Outstanding, Basic									694	707	706
Weighted Average Number of Shares Outstanding, Diluted									694	707	706
Income (Loss) from Continuing Operations, Per Basic Share	$ 0.70	$ 1.36	$ 0.87	$ 1.09	$ 0.14	$ 1.25	$ 1.02	$ 1.05	$ 4.02	$ 3.46	$ 3.64
Income (Loss) from Continuing Operations, Per Diluted Share	$ 0.70	$ 1.36	$ 0.87	$ 1.09	$ 0.14	$ 1.25	$ 1.02	$ 1.05	$ 4.02	$ 3.46	$ 3.63
Common Class A [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Income (Loss) from Continuing Operations Attributable to Parent									$ 2,791	$ 2,446	$ 2,565
Weighted Average Number of Shares Outstanding, Basic									694	707	706
Weighted Average Number of Shares Outstanding, Diluted									694	707	706
Income (Loss) from Continuing Operations, Per Basic Share									$ 4.02	$ 3.46	$ 3.64
Income (Loss) from Continuing Operations, Per Diluted Share									$ 4.02	$ 3.46	$ 3.63
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount									2	2	2
Common Stock, Dividends, Per Share, Declared									$ 3.24	$ 3.15	$ 3.09