| Schedule of Long-term Debt Instruments [Table Text Block] | 
Long-Term Debt 
Our indebtedness is carried at amortized cost net of applicable hedge adjustments. 
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(In Millions)  | 
   | 
Sep 30,  2017  | 
   | 
Dec 31,  2016  | 
 
Floating-rate senior notes:  | 
   | 
   | 
   | 
   | 
 
$700, three-month LIBOR plus 0.08%, due May 2020  | 
   | 
$  | 
700  | 
 
  | 
   | 
$  | 
—  | 
 
  | 
 
$800, three-month LIBOR plus 0.35%, due May 2022  | 
   | 
800  | 
 
  | 
   | 
—  | 
 
  | 
 
Fixed-rate senior notes:  | 
   | 
   | 
   | 
   | 
 
$500, 1.75%, due May 2017  | 
   | 
—  | 
 
  | 
   | 
501  | 
 
  | 
 
$3,000, 1.35%, due December 2017  | 
   | 
3,000  | 
 
  | 
   | 
2,999  | 
 
  | 
 
$600, 2.50%, due November 2018  | 
   | 
602  | 
 
  | 
   | 
604  | 
 
  | 
 
A$250, 3.25%, due December 20191
  | 
   | 
196  | 
 
  | 
   | 
180  | 
 
  | 
 
$1,000, 1.85%, due May 2020  | 
   | 
1,000  | 
 
  | 
   | 
—  | 
 
  | 
 
$1,750, 2.45%, due July 2020  | 
   | 
1,749  | 
 
  | 
   | 
1,749  | 
 
  | 
 
$500, 1.70%, due May 2021  | 
   | 
499  | 
 
  | 
   | 
499  | 
 
  | 
 
$2,000, 3.30%, due October 2021  | 
   | 
1,995  | 
 
  | 
   | 
1,988  | 
 
  | 
 
$750, 2.35%, due May 2022  | 
   | 
747  | 
 
  | 
   | 
—  | 
 
  | 
 
$1,000, 3.10%, due July 2022  | 
   | 
994  | 
 
  | 
   | 
987  | 
 
  | 
 
A$550, 4.00%, due December 20221
  | 
   | 
431  | 
 
  | 
   | 
394  | 
 
  | 
 
$1,500, 2.70%, due December 2022  | 
   | 
1,491  | 
 
  | 
   | 
1,480  | 
 
  | 
 
$400, 4.10%, due November 2023  | 
   | 
421  | 
 
  | 
   | 
424  | 
 
  | 
 
$1,250, 2.88%, due May 2024  | 
   | 
1,242  | 
 
  | 
   | 
—  | 
 
  | 
 
$600, 2.70%, due June 2024  | 
   | 
596  | 
 
  | 
   | 
—  | 
 
  | 
 
$2,250, 3.70%, due July 2025  | 
   | 
2,177  | 
 
  | 
   | 
2,148  | 
 
  | 
 
$1,000, 2.60%, due May 2026  | 
   | 
993  | 
 
  | 
   | 
983  | 
 
  | 
 
$1,000, 3.15%, due May 2027  | 
   | 
991  | 
 
  | 
   | 
—  | 
 
  | 
 
$750, 4.00%, due December 2032  | 
   | 
745  | 
 
  | 
   | 
745  | 
 
  | 
 
$1,500, 4.80%, due October 2041  | 
   | 
1,491  | 
 
  | 
   | 
1,491  | 
 
  | 
 
$925, 4.25%, due December 2042  | 
   | 
924  | 
 
  | 
   | 
924  | 
 
  | 
 
$2,000, 4.90%, due July 2045  | 
   | 
1,999  | 
 
  | 
   | 
1,999  | 
 
  | 
 
$1,007, 4.90%, due August 2045  | 
   | 
—  | 
 
  | 
   | 
995  | 
 
  | 
 
$915, 4.70%, due December 2045  | 
   | 
910  | 
 
  | 
   | 
894  | 
 
  | 
 
$1,250, 4.10%, due May 2046  | 
   | 
1,243  | 
 
  | 
   | 
1,243  | 
 
  | 
 
$1,000, 4.10%, due May 2047  | 
   | 
994  | 
 
  | 
   | 
—  | 
 
  | 
 
$640, 4.10%, due August 2047  | 
   | 
638  | 
 
  | 
   | 
—  | 
 
  | 
 
Junior subordinated convertible debentures:  | 
   | 
   | 
   | 
   | 
 
$1,600, 2.95%, due December 2035  | 
   | 
1,004  | 
 
  | 
   | 
992  | 
 
  | 
 
$2,000, 3.25%, due August 2039  | 
   | 
1,130  | 
 
  | 
   | 
1,118  | 
 
  | 
 
Long-term debt  | 
   | 
31,702  | 
 
  | 
   | 
25,337  | 
 
  | 
 
Less: current portion of long-term debt  | 
   | 
(4,129  | 
)  | 
   | 
(4,618  | 
)  | 
 
Less: debt issuance costs  | 
   | 
(75  | 
)  | 
   | 
(70  | 
)  | 
 
Total long-term debt  | 
   | 
$  | 
27,498  | 
 
  | 
   | 
$  | 
20,649  | 
 
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