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, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Net income before non-controlling interests	$ 379	$ 320	$ 580	$ 767	$ 396	$ 306	$ 344	$ 727	$ 2,046	$ 1,773	$ 1,670
Less: Net income attributable to non-controlling interests									30	31	20
Net income attributable to the Company	$ 374	$ 316	$ 572	$ 754	$ 391	$ 303	$ 332	$ 716	$ 2,016	$ 1,742	$ 1,650
Basic weighted average common shares outstanding (in shares)									506	506	506
Dilutive effect of potentially issuable common shares (in shares)									6	5	5
Diluted weighted average common shares outstanding (in shares)									512	511	511
Average stock price used to calculate common stock equivalents (in dollars per share)									$ 109.12	$ 97.23	$ 83.13