Summary of Significant Accounting Policies (Basic and Diluted EPS Calculation for Continuing Operations) (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
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Income from continuing operations	$ 380	$ 329	$ 429	$ 498	$ 269	$ 305	$ 440	$ 457	$ 1,636	$ 1,471	$ 1,379
Less: Net income attributable to non-controlling interests									37	32	28
Net income attributable to the Company									$ 1,599	$ 1,439	$ 1,351
Basic weighted average common shares outstanding (in shares)									531	545	549
Dilutive effect of potentially issuable common shares (in shares)									5	8	9
Dilutive weighted average common shares outstanding (in shares)									536	553	558
Average stock price used to calculate common stock equivalents (in dollars per share)									$ 56.27	$ 51.15	$ 40.97