Income Taxes (Tables)

3 Months Ended

Mar. 31, 2016

Income Tax Disclosure [Abstract]

Schedule of Changes in Unrecognized Tax Benefits

The following table presents changes in unrecognized tax benefits:

	As of/For the Year-to-Date Period Ended
	March 31, 2016			December 31, 2015
	(Dollars in millions)
Beginning balance of unrecognized tax benefits	$	426		$	503
Additions (reductions) for tax positions of prior years	(5		)	(76		)
Settlements	(417		)	(1		)
Lapse of statute of limitations	—			(1		)
Unrecognized deferred tax benefits from acquisitions	—			1
Ending balance of unrecognized tax benefits	$	4		$	426
Unrecognized tax benefits that would have impacted effective rate if recognized
Federal	$	—		$	422
State	3			3