@Arminius
(a) Let me assume that of the US$110K foreign income ( from Swiss lump sum pension ) you contributed US$40K, thus the employer's contribution plus growth is US$70K. In such a case the taxable amount ( for US purposes ) is US$ 70 K. Note that you need to be able to establish ( if challenged ) the your actual contribution over the years of employment at the then exchanged rate between Swiss Franc and US$. You will need these figures so you can essentially fill out a dummy 1099-R--- using total amount received, in Box-1; Taxable amount in Box-2a, click Total Distribution; Box 4 , federal Taxes withheld as 0 and distribution code of 7 ( normal distribution ). It may help to hand fill this on a form 1099-R ( downloaded from www. irs.gov ) for reference.
(b) Now go to TurboTax and enter all your pension and Social Security incomes as usual; also enter this foreign income as if this was on a 1099-R ( you can tell TurboTax that this is pension and that you did not get a 1099-R -- see (a) above.
(c) Then under deduction/ credits go through lists of deductions/credits till you find foreign tax credit . Herein choose that you want to take foreign tax credit. This will allow TurboTax to guide you in preparing a form 1116 -- where you have to enter the foreign income ( for purposes of this form only ) the total foreign income i.e. your figure of $110 K ( i.e. the amount before Switzerland took the US$ 4K tax out ). and of course the amount of foreign Taxes paid.
What this will result in is US taxing your world income of US$202 K and at that marginal rate ( so most of Social Security income will be taxable, some credits would go away etc. etc. ). Then TurboTax will calculate the US tax on the world income and thereafter allow a credit to you based on a ratio ( indirectly) of Foreign income to World income -- thus in your case because your US and foreign incomes are substantially equal, you should get most of your foreign taxes credited/ allowed ( implying that you may not have any tax on the foreign income ).
Is there more I can do for you ?
pk
