Shareholders' Equity (Shareholders' Equity, Accumulated Other Comprehensive Loss, Common Stock, and Preferred Stock) (Details) - USD ($)		12 Months Ended
		Dec. 31, 2019	Dec. 31, 2018
Class of Stock [Line Items]
Issued		1,068,000,000	1,069,000,000
In treasury		(190,000,000)	(198,000,000)
Total shares of common stock outstanding		878,000,000	871,000,000
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Defined benefit and other postretirement liability adjustments	[1]	$ (214,000,000)	$ (203,000,000)
Cumulative translation adjustment		(82,000,000)	(82,000,000)
Other		(66,000,000)	(70,000,000)
Total accumulated other comprehensive loss		$ (362,000,000)	$ (355,000,000)
Common Stock, Number of Shares, Par Value and Other Disclosures [Abstract]
Stock Repurchased During Period, Shares		4,500,000	10,500,000
Treasury Stock, Value, Acquired, Cost Method		$ 100,000,000
Stock authorized to repurchase		$ 5,200,000,000
Number of shares of common stock repurchased from inception (in shares)		217,000,000
Approximate value of shares of common stock repurchased from inception		$ 8,900,000,000
Preferred Stock, Number of Shares, Par Value and Other Disclosures [Abstract]
Number of shares of preferred stock that are authorized for issuance (in shares)		5,000,000
Number of shares preferred stock that are issued at period end (in shares)		0
Foreign Plan [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Net actuarial losses		$ 189,000,000	$ 184,000,000

[1] Included net actuarial losses for our international pension plans of $189 million at December 31, 2019 and $184 million at December 31, 2018.