The bills specifically state that Americans living overseas will not be subject to a tax.
Just to be boringly pedantic:
HR3590, Part A, Subtitle F, Section 5000A
`(4) INDIVIDUALS RESIDING OUTSIDE UNITED STATES OR RESIDENTS OF TERRITORIES- Any applicable individual shall be treated as having minimum essential coverage for any month--
`(A) if such month occurs during any period described in subparagraph (A) or (B) of section 911(d)(1) which is applicable to the individual, or
`(B) if such individual is a bona fide resident of any possession of the United States (as determined under section 937(a)) for such month.
Internal Revenue Code:Sec. 911
(d) Definitions and special rules
For purposes of this section -
(1) Qualified individual
The term ''qualified individual'' means an individual whose tax
home is in a foreign country and who is -
(A) a citizen of the United States and establishes to the
satisfaction of the Secretary that he has been a bona fide
resident of a foreign country or countries for an uninterrupted
period which includes an entire taxable year, or
(B) a citizen or resident of the United States and who,
during any period of 12 consecutive months, is present in a
foreign country or countries during at least 330 full days in
such period.
There are penalties for "Cadillac" plans, incomes over a certain amount, and those who file itemized deductions. I've not seen clarification if these apply regards those who meet the above requirements.