Debt Financing Arrangements (Long-Term Debt) (Details) € in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2020 EUR (€)	Sep. 28, 2020	Aug. 26, 2020 USD ($)	Jun. 30, 2020
Debt Instruments [Line Items]
Long-term Debt	$ 7,887	$ 7,679
Current maturities	(2)	(7)
Total long-term debt	7,885	7,672
Notes One Point Seventy Five Percent Due In Two Thousand Twenty-Three [Member]
Debt Instruments [Line Items]
Long-term Debt	$ 731	669
Debt Instrument, Face Amount | €			€ 600
Debt Instrument, Interest Rate, Stated Percentage	1.75%		1.75%
Debt instrument, maturity year	2023
Notes Four Point Five Percent due Two Thousand Forty-Nine [Member]
Debt Instruments [Line Items]
Long-term Debt	$ 588	587
Debt Instrument, Face Amount	$ 600
Debt Instrument, Interest Rate, Stated Percentage	4.50%		4.50%
Debt instrument, maturity year	2049
Notes Two Point Five Percent Due in Two Thousand Twenty-Six [Member]
Debt Instruments [Line Items]
Long-term Debt	$ 995	994
Debt Instrument, Face Amount	$ 1,000
Debt Instrument, Interest Rate, Stated Percentage	2.50%		2.50%
Debt instrument, maturity year	2026
Notes One Percent Due in Two Thousand Twenty-Five [Member]
Debt Instruments [Line Items]
Long-term Debt	$ 789	723
Debt Instrument, Face Amount | €			€ 650
Debt Instrument, Interest Rate, Stated Percentage	1.00%		1.00%
Debt instrument, maturity year	2025
Debentures four point four seven nine percent due in two thousand twenty one [Member]
Debt Instruments [Line Items]
Long-term Debt	$ 0	500
Debt Instrument, Face Amount		$ 516
Debt Instrument, Interest Rate, Stated Percentage		4.479%				4.479%
Debt instrument, maturity year		2021
Notes Three Point Seventy-Five Percent Due in Two Thousand Forty-Seven [Member]
Debt Instruments [Line Items]
Long-term Debt	402	$ 493
Debt Instrument, Face Amount	$ 408	500
Debt Instrument, Interest Rate, Stated Percentage	3.75%		3.75%
Debt instrument, maturity year	2047
Debentures five point three seven five percent due in two thousand thirty five [Member}
Debt Instruments [Line Items]
Long-term Debt	$ 424	461
Debt Instrument, Face Amount	$ 432	470
Debt Instrument, Interest Rate, Stated Percentage	5.375%		5.375%
Debt instrument, maturity year	2035
Notes Three Point Three Hundred Seventy-Five Percent due in Two Thousand Twenty-Two [Member]
Debt Instruments [Line Items]
Long-term Debt	$ 0	398
Debt Instrument, Face Amount		$ 400
Debt Instrument, Interest Rate, Stated Percentage		3.375%		3.375%
Debt instrument, maturity year		2022
Debentures five point seven six five percent due in two thousand forty one [Member]
Debt Instruments [Line Items]
Long-term Debt	297	$ 378
Debt Instrument, Face Amount	$ 297	378
Debt Instrument, Interest Rate, Stated Percentage	5.765%		5.765%
Debt instrument, maturity year	2041
Debentures five point nine three five percent due in two thousand thirty two [Member]
Debt Instruments [Line Items]
Long-term Debt	$ 333	379
Debt Instrument, Face Amount	$ 336	383
Debt Instrument, Interest Rate, Stated Percentage	5.935%		5.935%
Debt instrument, maturity year	2032
Debentures four point zero one six percent due in two thousand forty three [Member]
Debt Instruments [Line Items]
Long-term Debt	$ 255	389
Debt Instrument, Face Amount	$ 371	570
Debt Instrument, Interest Rate, Stated Percentage	4.016%		4.016%
Debt instrument, maturity year	2043
Debentures four point five three five percent due in two thousand forty two [Member]
Debt Instruments [Line Items]
Long-term Debt	$ 281	384
Debt Instrument, Face Amount	$ 383	528
Debt Instrument, Interest Rate, Stated Percentage	4.535%		4.535%
Debt instrument, maturity year	2042
Debentures seven percent due in two thousand thirty one [Member]
Debt Instruments [Line Items]
Long-term Debt	$ 159	163
Debt Instrument, Face Amount	$ 160	164
Debt Instrument, Interest Rate, Stated Percentage	7.00%		7.00%
Debt instrument, maturity year	2031
Debentures six point six two five percent due in two thousand twenty nine [Member]
Debt Instruments [Line Items]
Long-term Debt	$ 144	159
Debt Instrument, Face Amount	$ 144	160
Debt Instrument, Interest Rate, Stated Percentage	6.625%		6.625%
Debt instrument, maturity year	2029
Debentures six point ninety-five due in two thousand ninety seven [Member]
Debt Instruments [Line Items]
Long-term Debt	$ 154	155
Debt Instrument, Face Amount	$ 157	159
Debt Instrument, Interest Rate, Stated Percentage	6.95%		6.95%
Debt instrument, maturity year	2097
Debentures seven point five percent due in two thousand twenty seven [Member]
Debt Instruments [Line Items]
Long-term Debt	$ 146	150
Debt Instrument, Face Amount	$ 147	150
Debt Instrument, Interest Rate, Stated Percentage	7.50%		7.50%
Debt instrument, maturity year	2027
Debentures six point forty-five percent due in two thousand thirty eight [Member]
Debt Instruments [Line Items]
Long-term Debt	$ 102	126
Debt Instrument, Face Amount	$ 103	127
Debt Instrument, Interest Rate, Stated Percentage	6.45%		6.45%
Debt instrument, maturity year	2038
Debentures six point seventy-five percent due in two thousand twenty seven [Member]
Debt Instruments [Line Items]
Long-term Debt	$ 103	117
Debt Instrument, Face Amount	$ 103	118
Debt Instrument, Interest Rate, Stated Percentage	6.75%		6.75%
Debt instrument, maturity year	2027
Other [Member]
Debt Instruments [Line Items]
Long-term Debt	$ 174	454
Notes Two Point Twenty-Five Percent Due in 2030
Debt Instruments [Line Items]
Long-term Debt	987	0
Debt Instrument, Face Amount	$ 1,000
Debt Instrument, Interest Rate, Stated Percentage	3.25%		3.25%
Debt instrument, maturity year	2030
Notes Two Point Seventy-Five Percent, Due in 2025
Debt Instruments [Line Items]
Long-term Debt	$ 493	0
Debt Instrument, Face Amount	$ 500
Debt Instrument, Interest Rate, Stated Percentage	2.75%		2.75%
Debt instrument, maturity year	2025
Bonds Zero Percent Due in 2023 [Member]
Debt Instruments [Line Items]
Long-term Debt	$ 330	$ 0
Debt Instrument, Face Amount					$ 300
Debt Instrument, Interest Rate, Stated Percentage					0.00%
Debt instrument, maturity year	2023