Fair Value Of Financial Instruments (Fair Value Of Long-Term Debt) (Details) - USD ($) $ in Millions	Jun. 30, 2021	Dec. 31, 2020
Successor [Member] | Carrying Amount [Member]
Long-term debt [Abstract]
Total debt	$ 7,022
Successor [Member] | Fair Value [Member]
Long-term debt [Abstract]
Total debt	$ 7,105
Predecessor [Member] | Carrying Amount [Member]
Long-term debt [Abstract]
Total debt		$ 16,769
Predecessor [Member] | Fair Value [Member]
Long-term debt [Abstract]
Total debt		$ 11,635