Credit Losses - In 2016, the Financial Accounting Standards Board issued an accounting standard requiring use of a current expected credit loss model rather than an incurred loss method, which is intended to result in more timely recognition of credit losses on trade receivables, certain other assets and off-balance sheet credit exposures. Alliant Energy, IPL and WPL adopted this standard on January 1, 2020 using a modified retrospective method of adoption, which required cumulative effect adjustments to retained earnings on January 1, 2020. IPL and WPL did not record a cumulative effect adjustment to retained earnings and Alliant Energy recorded a pre-tax $12 million (after-tax $9 million) cumulative effect adjustment to decrease retained earnings related to Alliant Energy’s guarantees in the partnership obligations of an affiliate of Whiting Petroleum (refer to Note 17(d) for further discussion). This adjustment is included in “Adoption of new accounting standard” in Alliant Energy’s equity statement for 2020.

About New Standards Disclosures

New accounting standards disclosures describe recently adopted pronouncements and those not yet effective, along with management's assessment of their expected impact. This section provides an early warning system for upcoming changes to how a company reports its financial results, often years before the new rules take effect.

Key signals: when management describes a not-yet-adopted standard's impact as "material" or "still being evaluated," it signals potential significant changes to reported metrics upon adoption. Watch for standards that affect a company's core operations — for example, revenue recognition changes for software companies or lease accounting changes for retailers with large store footprints. The transition method chosen (full retrospective versus modified retrospective) affects comparability with prior periods. Companies that delay adoption to the latest permitted date may be struggling with implementation complexity. Compare the disclosed impact assessments against peers in the same industry to gauge whether management's expectations are reasonable.