Debt Financing Arrangements (Narrative) (Details) € in Millions, $ in Millions						3 Months Ended	12 Months Ended
	Dec. 03, 2018 USD ($)	Sep. 12, 2018 USD ($)	Sep. 29, 2017 USD ($)	Sep. 14, 2017 USD ($)	Apr. 15, 2017 USD ($)	Sep. 30, 2017 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2018 EUR (€)	Dec. 03, 2018 EUR (€)	Sep. 12, 2018 EUR (€)
Debt And Financing Arrangements [Line Items]
Extinguishment of Debt, Amount						$ 559		$ 559
Debt Instrument, Issuance Date	Dec. 03, 2018
Proceeds from long-term debt borrowings							$ 1,762	532	$ 1,041
Discount amortization expense included in interest expense related to the notes							10	$ 11	9
Excess of fair value over carrying value of long-term debt							700
Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months							582
Long-term Debt, Maturities, Repayments of Principal in Year Two							16
Long-term Debt, Maturities, Repayments of Principal in Year Three							666
Long-term Debt, Maturities, Repayments of Principal in Year Four							409
Long-term Debt, Maturities, Repayments of Principal in Year Five							11
Lines of credit							10,400
Unused lines of credit							$ 8,900
Weighted average interest rate on short term borrowings (as a percent)							7.95%	2.35%		7.95%
Outstanding standby letters of credit and surety bonds							$ 1,700	$ 1,200
Gains (Losses) on Extinguishment of Debt							$ 0	$ (11)	$ 0
Notes Four Point Five Percent due Two Thousand Forty-Nine [Member]
Debt And Financing Arrangements [Line Items]
Debt Instrument, Interest Rate, Stated Percentage											4.50%
Proceeds from notes recorded as long-term debt	$ 588
Debt Instrument, Face Amount | €											€ 600
Debt Instrument, Maturity Date	Mar. 15, 2049
Notes Three Point Three Hundred Seventy-Five Percent due in Two Thousand Twenty-Two [Member]
Debt And Financing Arrangements [Line Items]
Debt Instrument, Interest Rate, Stated Percentage											3.375%
Proceeds from notes recorded as long-term debt	$ 399
Debt Instrument, Face Amount | €											€ 400
Debt Instrument, Maturity Date	Mar. 15, 2022
Notes One Percent Due in Two Thousand Twenty-Five [Member]
Debt And Financing Arrangements [Line Items]
Debt Instrument, Issuance Date		Sep. 12, 2018
Debt Instrument, Interest Rate, Stated Percentage							1.00%			1.00%		1.00%
Proceeds from notes recorded as long-term debt		$ 747
Debt Instrument, Face Amount							$ 744			€ 650		€ 650
Debt Instrument, Maturity Date		Sep. 12, 2025					Sep. 12, 2025
Notes Three Point Seventy-Five Percent Due in Two Thousand Forty-Seven [Member]
Debt And Financing Arrangements [Line Items]
Debt Instrument, Issuance Date				Sep. 14, 2017
Debt Instrument, Interest Rate, Stated Percentage				3.75%			3.75%			3.75%
Debt Instrument, Face Amount				$ 500			$ 500
Debt Instrument, Maturity Date				Sep. 15, 2047			Sep. 15, 2047
Proceeds from Issuance of Debt				$ 493
Notes Two Point Five Percent Due in Two Thousand Twenty-Six [Member]
Debt And Financing Arrangements [Line Items]
Debt Instrument, Interest Rate, Stated Percentage							2.50%			2.50%
Debt instrument, maturity year							2026
Debt Instrument, Face Amount							$ 1,000
Notes One Point Seventy Five Percent Due In Two Thousand Twenty-Three [Member]
Debt And Financing Arrangements [Line Items]
Debt Instrument, Interest Rate, Stated Percentage							1.75%			1.75%
Debt instrument, maturity year							2023
Debt Instrument, Face Amount | €										€ 600
Notes Five Point Forty-Five Percent Due In Two Thousand Eighteen [Member]
Debt And Financing Arrangements [Line Items]
Debt Instrument, Repurchase Date			Sep. 29, 2017
Extinguishment of Debt, Amount			$ 559
Debt Instrument, Interest Rate, Stated Percentage			5.45%					5.45%
Debt Instrument, Face Amount								$ 559
Debt Instrument, Maturity Date			Mar. 15, 2018					Mar. 15, 2018
Gains (Losses) on Extinguishment of Debt								$ (11)
Floating Rate Notes Due In Two Thousand Nineteen [Member]
Debt And Financing Arrangements [Line Items]
Debt instrument, maturity year							2019
Debt Instrument, Face Amount | €										€ 500
Debentures four point four seven nine percent due in two thousand twenty one [Member]
Debt And Financing Arrangements [Line Items]
Debt Instrument, Interest Rate, Stated Percentage							4.479%			4.479%
Debt instrument, maturity year							2021
Debt Instrument, Face Amount							$ 516
Debentures five point three seven five percent due in two thousand thirty five [Member}
Debt And Financing Arrangements [Line Items]
Debt Instrument, Interest Rate, Stated Percentage							5.375%			5.375%
Debt instrument, maturity year							2035
Debt Instrument, Face Amount							$ 470
Debentures five point seven six five percent due in two thousand forty one [Member]
Debt And Financing Arrangements [Line Items]
Debt Instrument, Interest Rate, Stated Percentage							5.765%			5.765%
Debt instrument, maturity year							2041
Debt Instrument, Face Amount							$ 378
Debentures five point nine three five percent due in two thousand thirty two [Member]
Debt And Financing Arrangements [Line Items]
Debt Instrument, Interest Rate, Stated Percentage							5.935%			5.935%
Debt instrument, maturity year							2032
Debt Instrument, Face Amount							$ 383
Debentures four point zero one six percent due in two thousand forty three [Member]
Debt And Financing Arrangements [Line Items]
Debt Instrument, Interest Rate, Stated Percentage							4.016%			4.016%
Debt instrument, maturity year							2043
Debt Instrument, Face Amount							$ 570
Debentures four point five three five percent due in two thousand forty two [Member]
Debt And Financing Arrangements [Line Items]
Debt Instrument, Interest Rate, Stated Percentage							4.535%			4.535%
Debt instrument, maturity year							2042
Debt Instrument, Face Amount							$ 528
Debentures eight point three seven five percent due in two thousand seventeen [ Member]
Debt And Financing Arrangements [Line Items]
Debt Instrument, Interest Rate, Stated Percentage					8.375%			8.375%
Debt Instrument, Face Amount					$ 261			$ 261
Debt Instrument, Maturity Date					Apr. 15, 2017			Apr. 15, 2017
Debentures seven percent due in two thousand thirty one [Member]
Debt And Financing Arrangements [Line Items]
Debt Instrument, Interest Rate, Stated Percentage							7.00%			7.00%
Debt instrument, maturity year							2031
Debt Instrument, Face Amount							$ 164
Debentures six point six two five percent due in two thousand twenty nine [Member]
Debt And Financing Arrangements [Line Items]
Debt Instrument, Interest Rate, Stated Percentage							6.625%			6.625%
Debt instrument, maturity year							2029
Debt Instrument, Face Amount							$ 160
Debentures six point ninety-five due in two thousand ninety seven [Member]
Debt And Financing Arrangements [Line Items]
Debt Instrument, Interest Rate, Stated Percentage							6.95%			6.95%
Debt instrument, maturity year							2097
Debt Instrument, Face Amount							$ 159
Debentures seven point five percent due in two thousand twenty seven [Member]
Debt And Financing Arrangements [Line Items]
Debt Instrument, Interest Rate, Stated Percentage							7.50%			7.50%
Debt instrument, maturity year							2027
Debt Instrument, Face Amount							$ 150
Debentures six point forty-five percent due in two thousand thirty eight [Member]
Debt And Financing Arrangements [Line Items]
Debt Instrument, Interest Rate, Stated Percentage							6.45%			6.45%
Debt instrument, maturity year							2038
Debt Instrument, Face Amount							$ 127
Debentures six point seventy-five percent due in two thousand twenty seven [Member]
Debt And Financing Arrangements [Line Items]
Debt Instrument, Interest Rate, Stated Percentage							6.75%			6.75%
Debt instrument, maturity year							2027
Debt Instrument, Face Amount							$ 118
Commercial Paper [Member]
Debt And Financing Arrangements [Line Items]
Lines of credit							5,000
Amount utilized from lines of credit facility							0
Accounts Receivable Securitization Facility [Member]
Debt And Financing Arrangements [Line Items]
Lines of credit							1,800
Amount utilized from lines of credit facility							$ 1,500