Quarterly Financial Data (Schedule Of Quarterly Financial Data) (Details) - USD ($) $ / shares in Units, $ in Millions	1 Months Ended			3 Months Ended								12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Oct. 31, 2014	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
Schedule of Quarterly Financial Information [Line Items]
Total revenues				$ 23,573	$ 25,849	$ 24,543	$ 22,149	$ 24,468	$ 23,784	$ 22,045	$ 20,465	$ 96,114	$ 90,762	$ 86,623
Total costs and expenses				(20,642)	(21,600)	(21,350)	(18,496)	(20,711)	(20,075)	(18,670)	(17,296)	(82,088)	(76,752)	(73,268)
Earnings from operations				1,161	2,580	1,683	2,019	2,025	2,119	1,787	1,542	7,443	7,473	6,562
Net earnings				$ 1,026	$ 1,704	$ 1,110	$ 1,336	$ 1,466	$ 1,362	$ 1,653	$ 965	$ 5,176	$ 5,446	$ 4,585
Basic earnings per share				$ 1.52	$ 2.50	$ 1.61	$ 1.89	$ 2.05	$ 1.88	$ 2.26	$ 1.30	$ 7.52	$ 7.47	$ 6.03
Diluted earnings per share				1.51	2.47	1.59	1.87	2.02	1.86	2.24	1.28	7.44	7.38	5.96
Cash dividends declared, per share	$ 1.09	$ 0.91	$ 0.73	2.00		1.82		1.64		1.46		3.82	3.10	$ 2.185
Common stock sales price per share, Quarter end	$ 144.59	$ 129.98		144.59	130.95	138.72	150.08	129.98	127.38	127.23	125.49	$ 144.59	$ 129.98
Maximum [Member]
Schedule of Quarterly Financial Information [Line Items]
Common stock sales price per share				150.59	149.18	155.50	158.83	135.78	130.58	138.39	144.57
Minimum [Member]
Schedule of Quarterly Financial Information [Line Items]
Common stock sales price per share				$ 128.56	$ 115.14	$ 138.44	$ 126.18	$ 116.32	$ 117.87	$ 121.92	$ 118.77