(Millions)

June 30, 2018

December 31, 2017

Corporate debt securities

$

 —

$

14

Commercial paper

347

899

Certificates of deposit/time deposits

31

76

U.S. municipal securities

 4

 3

Asset-backed securities:

Automobile loan related

 3

16

Credit card related

 —

68

Asset-backed securities total

 3

84

Current marketable securities

$

385

$

1,076

U.S. municipal securities

$

26

$

27

Non-current marketable securities

$

26

$

27

Total marketable securities

$

411

$

1,103