Goodwill and Other Acquired Intangible Assets Goodwill activity (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Goodwill [Roll Forward]
Goodwill, beginning of period	$ 9,822,050	$ 9,734,348
Accumulated impairment losses, beginning of period	(4,775,203)	(4,762,703)
Goodwill, net, beginning of period	5,046,847	4,971,645
Goodwill acquired during the year	13,350	89,401
Disposition adjustments	0	(1,699)
Impairment losses	(17,000)	(12,500)	$ 0
Goodwill, end of period	9,835,400	9,822,050	9,734,348
Accumulated impairment losses, end of period	(4,792,203)	(4,775,203)	(4,762,703)
Goodwill, net, end of period	$ 5,043,197	$ 5,046,847	$ 4,971,645