v3.3.1.900
Income Taxes (Reconciliation of Unrecognized Tax Benefits) (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2015
Dec. 31, 2014
Dec. 31, 2013
Income Taxes [Abstract]      
Beginning balance $ 1,171 $ 1,701 $ 1,573
Additions based on tax positions related to the current year 67 63 90
Additions based on tax positions related to prior years 98 111 201
Additions from acquired subsidiaries 0 0 268
Reductions for tax positions of prior years (84) (220) (141)
Reductions due to expiration of statutes of limitations (41) (448) (3)
Settlements with taxing authorities (75) (36) (287)
Ending balance $ 1,136 $ 1,171 $ 1,701