Revision of Prior Period Financial Statements - Schedule of Consolidated Income (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended													6 Months Ended	9 Months Ended				12 Months Ended
	Sep. 30, 2024		Jun. 30, 2024	[2]	Mar. 31, 2024		Dec. 31, 2023	Sep. 30, 2023		Jun. 30, 2023		Mar. 31, 2023		Jun. 30, 2023	Sep. 30, 2024	[1]	Sep. 30, 2023		Dec. 31, 2023	Dec. 31, 2022
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Labor and Fringe	$ 806				$ 805		$ 814	$ 761	[1]	$ 748		$ 729		$ 1,477	$ 2,377		$ 2,238	[1]	$ 3,052	$ 2,885
Purchased Services and Other	675				721		714	700	[1]	691		697		1,388	2,095		2,088	[1]	2,802	2,728
Depreciation and Amortization	416						405	403	[1]	404		395		799	1,236		1,202	[1]	1,607	1,502
Total Expense	2,265				2,344		2,365	2,301	[1]	2,233		2,259		4,492	6,862		6,793	[1]	9,158	8,899
Operating Income	1,354				1,337		1,315	1,271	[1]	1,466		1,447		2,913	4,139		4,184	[1]	5,499	5,954
Earnings Before Income Taxes	1,184				1,168		1,144	1,102	[1]	1,296		1,287		2,583	3,619		3,685	[1]	4,829	5,345
Income Tax Expense	(290)				(288)		(262)	(274)	[1]	(312)		(313)		(625)	(882)		(899)	[1]	(1,161)	(1,231)
Net Earnings	$ 894	[2]	$ 963		$ 880	[2]	$ 882	$ 828	[1]	$ 984	[3]	$ 974	[3]	$ 1,958	$ 2,737		$ 2,786	[1]	$ 3,668	$ 4,114
Net Earnings Per Share, Basic (in dollars per share)	$ 0.46				$ 0.45		$ 0.45	$ 0.42	[1]	$ 0.49		$ 0.47		$ 0.96	$ 1.41		$ 1.38	[1]	$ 1.83	$ 1.93
Net Earnings Per Share, Assuming Dilution (in dollars per share)	$ 0.46				$ 0.45		$ 0.45	$ 0.41	[1]	$ 0.49		$ 0.47		$ 0.96	$ 1.40		$ 1.37	[1]	$ 1.82	$ 1.92
Total Comprehensive Earnings (Note 10)	$ 895	[2]	$ 966		$ 886	[2]	$ 997	$ 846	[3]	$ 980	[3]	$ 976	[3]	$ 1,956	$ 2,747		$ 2,802	[1]	$ 3,799	$ 4,080
As Previously Reported
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Labor and Fringe					798		808	752		741		723		1,464			2,216		3,024	2,861
Purchased Services and Other					711		703	689		684		688		1,372			2,061		2,764	2,685
Depreciation and Amortization							417	399		402		393		795			1,194		1,611	1,500
Total Expense					2,327		2,360	2,277		2,217		2,242		4,459			6,736		9,096	8,830
Operating Income					1,354		1,320	1,295		1,482		1,464		2,946			4,241		5,561	6,023
Earnings Before Income Taxes					1,185		1,149	1,126		1,312		1,304		2,616			3,742		4,891	5,414
Income Tax Expense					(292)		(263)	(280)		(316)		(317)		(633)			(913)		(1,176)	(1,248)
Net Earnings					$ 893		$ 886	$ 846		$ 996		$ 987		$ 1,983			$ 2,829		$ 3,715	$ 4,166
Net Earnings Per Share, Basic (in dollars per share)					$ 0.46		$ 0.45	$ 0.42		$ 0.49		$ 0.48		$ 0.97			$ 1.40		$ 1.85	$ 1.95
Net Earnings Per Share, Assuming Dilution (in dollars per share)					$ 0.46		$ 0.45	$ 0.42		$ 0.49		$ 0.48		$ 0.97			$ 1.40		$ 1.85	$ 1.95
Total Comprehensive Earnings (Note 10)					$ 899		$ 946	$ 864		$ 992		$ 989		$ 1,981			$ 2,845		$ 3,791	$ 4,186
Adjustment
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Labor and Fringe					7		6	9		7		6		13			22		28	24
Purchased Services and Other					10		11	11		7		9		16			27		38	43
Depreciation and Amortization							(12)	4		2		2		4			8		(4)	2
Total Expense					17		5	24		16		17		33			57		62	69
Operating Income					(17)		(5)	(24)		(16)		(17)		(33)			(57)		(62)	(69)
Earnings Before Income Taxes					(17)		(5)	(24)		(16)		(17)		(33)			(57)		(62)	(69)
Income Tax Expense					4		1	6		4		4		8			14		15	17
Net Earnings					$ (13)		$ (4)	$ (18)		$ (12)		$ (13)		$ (25)			$ (43)		$ (47)	$ (52)
Net Earnings Per Share, Basic (in dollars per share)					$ (0.01)		$ 0	$ 0		$ 0		$ (0.01)		$ (0.01)			$ (0.02)		$ (0.02)	$ (0.02)
Net Earnings Per Share, Assuming Dilution (in dollars per share)					$ (0.01)		$ 0	$ (0.01)		$ 0		$ (0.01)		$ (0.01)			$ (0.03)		$ (0.03)	$ (0.03)
Total Comprehensive Earnings (Note 10)					$ (13)		$ 51	$ (18)		$ (12)		$ (13)		$ (25)			$ (43)		$ 8	$ (106)

[1] See Note 11, Revision of Prior Period Financial Statements.

[2] See Note 11, Revision of Prior Period Financial Statements.

[3] See Note 11, Revision of Prior Period Financial Statements.