The European Central Bank's governing council members wrestled with fears that falling prices could become ingrained in the economy before a "large majority" decided to launch an additional 1 trillion euro monetary boost.
That's according to an account of the ECB's closed-door deliberations on Jan. 22.
With the publication of the account, the ECB joins the U.S. Federal Reserve and the Bank of England, which both reveal minutes of their meetings weeks afterward.
The ECB acted after finding that the effect of earlier stimulus efforts such as cheap loans to banks "was more limited" than expected.
Some members argued the risk of outright deflation was "relatively small." That view ran into "broad agreement" that the risk "even if uncertain" was too great to hold off on taking action.