POWER OF ATTORNEY

Know all by these presents, that the undersigned hereby constitutes and appoints
each of Dwight W. Rettig and Brigitte M. Hunt, or either of them signing singly,
and with full power of substitution, the undersigned's true and lawful
attorney-in-fact to:

   (1)   execute for and on behalf of the undersigned, in the undersigned's
         capacity as an officer and/or director of National Oilwell Varco, Inc.
         (the "Company"), Forms 3, 4, and 5 in accordance with Section 16(a) of
         the Securities Exchange Act of 1934 and the rules thereunder;

   (2)   do and perform any and all acts for and on behalf of the
         undersigned which may be necessary or desirable to complete and execute
         any such Form 3, 4, or 5, complete and execute any amendment or
         amendments thereto, and timely file such form with the United States
         Securities and Exchange Commission and any stock exchange or similar
         authority; and

   (3)   take any other action of any type whatsoever in connection with the
         foregoing which, in the opinion of such attorney-in-fact, may be of
         benefit to, in the best interest of, or legally required by, the
         undersigned, it being understood that the documents executed by such
         attorney-in-fact on behalf of the undersigned pursuant to this Power of
         Attorney shall be in such form and shall contain such terms and
         conditions as such attorney-in-fact may approve in such attorney-in-
         fact's discretion.

The undersigned hereby grants to each such attorney-in-fact full power and
authority to do and perform any and every act and thing whatsoever requisite,
necessary, or proper to be done in the exercise of any of the rights and powers
herein granted, as fully to all intents and purposes as the undersigned might or
could do if personally present, with full power of substitution or revocation,
hereby ratifying and confirming all that such attorney-in-fact, or such
attorney-in-fact's substitute or substitutes, shall lawfully do or cause to be
done by virtue of this power of attorney and the rights and powers herein
granted. The undersigned acknowledges that the foregoing attorneys-in-fact, in
serving in such capacity at the request of the undersigned, are not assuming,
nor is the Company assuming, any of the undersigned's responsibilities to comply
with Section 16 of the Securities Exchange Act of 1934.

This Power of Attorney shall remain in full force and effect until the
undersigned is no longer required to file Forms 3, 4, and 5 with respect to the
undersigned's holdings of and transactions in securities issued by the Company,
unless earlier revoked by the undersigned in a signed writing delivered to the
foregoing attorneys-in-fact.  This Power of Attorney supersedes all previous
Powers of Attorney relating to the subject matter hereof.

IN WITNESS WHEREOF, the undersigned has caused this Power of Attorney to be
executed as of this 29th day of April, 2014.

/s/ Roger L. Jarvis
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Signature

Roger L. Jarvis
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