Short-Term Borrowings and Long-Term Debt (Details) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Par Value	$ 42,917	$ 39,817
Carrying value, Combined Amount	42,662	39,474
Fair Value	50,597	44,234
Commercial Paper [Member]
Debt Instrument [Line Items]
Commercial Paper	0	400
Par Value	0	400
Fair Value	$ 0	400
2.700% Notes due July 2020 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	2.70%
Par Value	$ 0	1,500
Carrying Value, Current	0	1,499
Fair Value	0	1,506
Floating rate notes due October 2020 [Member]
Debt Instrument [Line Items]
Par Value	300	300
Carrying Value, Current	300	300
Fair Value	$ 300	300
3.875% notes due October 2020 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	3.875%
Par Value	$ 450	450
Carrying Value, Current	450	450
Fair Value	$ 451	455
1.950% notes due October 2020 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	1.95%
Par Value	$ 900	900
Carrying Value, Current	900	899
Fair Value	$ 901	900
4.700% notes due February 2021 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	4.70%
Par Value	$ 400	400
Carrying Value, Current	403
Carrying Value, Noncurrent		403
Fair Value	$ 402	410
2.125% notes due March 2021 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	2.125%
Par Value	$ 750	750
Carrying Value, Current	749
Carrying Value, Noncurrent		749
Fair Value	756	753
Floating rate notes due June 2021 [Member]
Debt Instrument [Line Items]
Par Value	350	350
Carrying Value, Noncurrent	350	349
Fair Value	$ 351	350
3.150% notes due June 2021 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	3.15%
Par Value	$ 400	400
Carrying Value, Noncurrent	400	399
Fair Value	$ 408	407
3.375% notes due November 2021 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	3.375%
Par Value	$ 500	500
Carrying Value, Noncurrent	509	501
Fair Value	$ 513	512
2.875% notes due December 2021 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	2.875%
Par Value	$ 750	750
Carrying Value, Noncurrent	765	753
Fair Value	$ 774	765
2.875% notes due March 2022 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	2.875%
Par Value	$ 1,100	1,100
Carrying Value, Noncurrent	1,115	1,087
Fair Value	$ 1,133	1,121
3.350% notes due July 2022 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	3.35%
Par Value	$ 1,000	1,000
Carrying Value, Noncurrent	998	998
Fair Value	$ 1,054	1,036
2.375% notes due October 2022 [Member] [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	2.375%
Par Value	$ 900	900
Carrying Value, Noncurrent	897	896
Fair Value	$ 937	911
Zero Coupon notes due November 2022 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	0.00%
Par Value	$ 15	15
Carrying Value, Noncurrent	13	13
Fair Value	$ 14	14
2.750% notes due February 2023 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	2.75%
Par Value	$ 625	625
Carrying Value, Noncurrent	646	624
Fair Value	$ 656	638
2.875% notes due March 2023 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	2.875%
Par Value	$ 750	750
Carrying Value, Noncurrent	793	770
Fair Value	$ 794	770
3.500% notes due June 2023 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	3.50%
Par Value	$ 750	750
Carrying Value, Noncurrent	748	747
Fair Value	$ 811	786
3.500% notes due February 2024 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	3.50%
Par Value	$ 750	750
Carrying Value, Noncurrent	746	746
Fair Value	$ 825	792
2.375% notes due August 2024 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	2.375%
Par Value	$ 750	750
Carrying Value, Noncurrent	747	747
Fair Value	$ 799	760
3.750% notes due July 2025 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	3.75%
Par Value	$ 2,000	2,000
Carrying Value, Noncurrent	1,992	1,990
Fair Value	$ 2,283	2,161
3.700% notes due December 2025 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	3.70%
Par Value	$ 300	300
Carrying Value, Noncurrent	298	298
Fair Value	$ 343	325
1.250% notes due January 2026
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	1.25%
Par Value	$ 500	0
Carrying Value, Noncurrent	496	0
Fair Value	$ 513	0
3.100% notes due March 2026 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	3.10%
Par Value	$ 1,000	1,000
Carrying Value, Noncurrent	996	996
Fair Value	$ 1,118	1,048
3.450% notes due January 2027 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	3.45%
Par Value	$ 750	750
Carrying Value, Noncurrent	746	746
Fair Value	$ 853	804
3.375% notes due April 2027 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	3.375%
Par Value	$ 625	625
Carrying Value, Noncurrent	620	620
Fair Value	$ 713	667
2.950% notes due October 2027 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	2.95%
Par Value	$ 950	950
Carrying Value, Noncurrent	940	939
Fair Value	$ 1,060	988
3.850% notes due June 2028 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	3.85%
Par Value	$ 1,150	1,150
Carrying Value, Noncurrent	1,143	1,142
Fair Value	$ 1,357	1,269
3.875% notes due December 2028 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	3.875%
Par Value	$ 850	850
Carrying Value, Noncurrent	843	843
Fair Value	$ 1,010	941
2.875% notes due August 2029 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	2.875%
Par Value	$ 1,000	1,000
Carrying Value, Noncurrent	1,104	993
Fair Value	$ 1,115	1,029
2.000% notes due May 2030
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	2.00%
Par Value	$ 1,250	0
Carrying Value, Noncurrent	1,233	0
Fair Value	$ 1,310	0
4.625% notes due July 2035 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	4.625%
Par Value	$ 1,000	1,000
Carrying Value, Noncurrent	992	992
Fair Value	$ 1,317	1,215
5.800% notes due March 2036 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	5.80%
Par Value	$ 850	850
Carrying Value, Noncurrent	839	838
Fair Value	$ 1,231	1,129
6.500% Notes Due June 2037 [Member] [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	6.50%
Par Value	$ 500	500
Carrying Value, Noncurrent	492	492
Fair Value	$ 778	712
6.625% Notes due November 2037 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	6.625%
Par Value	$ 650	650
Carrying Value, Noncurrent	641	641
Fair Value	$ 1,027	940
6.875% notes due February 2038 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	6.875%
Par Value	$ 1,100	1,100
Carrying Value, Noncurrent	1,077	1,076
Fair Value	$ 1,772	1,631
3.500% notes due August 2039 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	3.50%
Par Value	$ 1,250	1,250
Carrying Value, Noncurrent	1,241	1,241
Fair Value	$ 1,436	1,313
2.750% notes due May 2040
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	2.75%
Par Value	$ 1,000	0
Carrying Value, Noncurrent	964	0
Fair Value	$ 1,057	0
5.700% notes due October 2040 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	5.70%
Par Value	$ 300	300
Carrying Value, Noncurrent	296	296
Fair Value	$ 438	396
5.950% notes due February 2041 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	5.95%
Par Value	$ 350	350
Carrying Value, Noncurrent	346	345
Fair Value	$ 525	475
4.625% notes due November 2041 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	4.625%
Par Value	$ 600	600
Carrying Value, Noncurrent	589	589
Fair Value	$ 787	716
4.375% notes due March 2042 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	4.375%
Par Value	$ 502	502
Carrying Value, Noncurrent	485	484
Fair Value	$ 639	580
3.950% notes due October 2042 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	3.95%
Par Value	$ 625	625
Carrying Value, Noncurrent	608	607
Fair Value	$ 760	688
4.250% notes due March 2043 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	4.25%
Par Value	$ 750	750
Carrying Value, Noncurrent	735	735
Fair Value	$ 949	856
4.750% notes due July 2045 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	4.75%
Par Value	$ 2,000	2,000
Carrying Value, Noncurrent	1,973	1,973
Fair Value	$ 2,730	2,463
4.200% notes due January 2047 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	4.20%
Par Value	$ 750	750
Carrying Value, Noncurrent	738	738
Fair Value	$ 950	861
4.250% notes due April 2047 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	4.25%
Par Value	$ 725	725
Carrying Value, Noncurrent	717	717
Fair Value	$ 923	839
3.750% notes due October 2047 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	3.75%
Par Value	$ 950	950
Carrying Value, Noncurrent	934	934
Fair Value	$ 1,130	1,023
4.250% notes due June 2048 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	4.25%
Par Value	$ 1,350	1,350
Carrying Value, Noncurrent	1,330	1,330
Fair Value	$ 1,721	1,569
4.450% notes due December 2048 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	4.45%
Par Value	$ 1,100	1,100
Carrying Value, Noncurrent	1,086	1,086
Fair Value	$ 1,457	1,316
3.700% notes due August 2049 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	3.70%
Par Value	$ 1,250	1,250
Carrying Value, Noncurrent	1,235	1,235
Fair Value	$ 1,496	1,344
2.900% notes due May 2050
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	2.90%
Par Value	$ 1,250	0
Carrying Value, Noncurrent	1,208	0
Fair Value	$ 1,318	0
3.875% notes due August 2059 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	3.875%
Par Value	$ 1,250	1,250
Carrying Value, Noncurrent	1,228	1,228
Fair Value	$ 1,529	1,350
3.125% notes due May 2060
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	3.125%
Par Value	$ 1,000	0
Carrying Value, Noncurrent	968	0
Fair Value	$ 1,073	$ 0