Contingencies, Commitments and Guarantees (Contingencies - Narrative) (Details) $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2020 USD ($) Claims	Mar. 31, 2019 Claims	Dec. 31, 2019 Claims
Minimum
Loss Contingencies
Loss Contingency, Range of Possible Loss, Portion Not Accrued	$ 0
Maximum
Loss Contingencies
Loss Contingency, Range of Possible Loss, Portion Not Accrued	$ 250
Asbestos Related Claims
Loss Contingencies
Asbestos-Related Claims | Claims	596	843	3,187